- A
The S3 bucket uses SSE-C encryption, and the EMR cluster does not have the encryption key.
Why wrong: SSE-C would cause a different error (InvalidArgument), not AccessDenied.
- B
The EMR service role does not have permissions to write to the S3 bucket.
Why wrong: The service role is used by EMR to manage resources; the actual data access uses the instance profile.
- C
The EMR cluster is not using a VPC endpoint for S3, so requests are denied by the bucket policy's VPC condition.
The bucket policy restricts access to VPC, but since the Spark job runs on EMR, its requests originate from inside the VPC only if a VPC endpoint is used; otherwise, they come from public IPs.
- D
The S3 bucket is configured with 'Bucket owner enforced' setting for ACLs, and the EMR cluster's account is not the bucket owner.
Why wrong: Bucket owner enforced affects ACLs, not IAM policy evaluation; access is still controlled by bucket policy.
Quick Answer
The answer is that the EMR cluster is not using a VPC endpoint for S3, so requests are denied by the bucket policy's VPC condition. This occurs because the S3 bucket policy explicitly restricts access to traffic originating from the VPC, typically using the `aws:SourceVpc` condition key. When the EMR cluster sends requests over the public internet instead of through a VPC endpoint (Gateway or Interface), those requests fail the condition check, resulting in the `S3AccessDeniedException`—even though the IAM roles are correctly configured. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of how VPC endpoints interact with S3 bucket policies, a common trap where candidates focus only on IAM permissions and overlook network-level restrictions. A key memory tip: if a bucket policy says “VPC only,” your EMR traffic must stay inside the VPC—think “no public road, use the VPC tunnel.”
DEA-C01 Data Store Management Practice Question
This DEA-C01 practice question tests your understanding of data store management. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company runs an Apache Spark job on Amazon EMR that writes output to an S3 bucket. The job fails with the error 'S3AccessDeniedException' when writing the final output, but earlier stages succeed. The EMR cluster uses a service role and an instance profile. The S3 bucket policy allows access from the VPC only. What is the MOST likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The EMR cluster is not using a VPC endpoint for S3, so requests are denied by the bucket policy's VPC condition.
The bucket policy restricts access to requests originating from the VPC, typically using a condition like `aws:SourceVpc`. If the EMR cluster does not use a VPC endpoint for S3 (either Gateway or Interface endpoint), traffic from the cluster to S3 traverses the public internet and does not match the VPC condition, causing the `S3AccessDeniedException`. Earlier stages may succeed if they use cached data or different paths, but the final write fails because it hits the bucket policy check.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The S3 bucket uses SSE-C encryption, and the EMR cluster does not have the encryption key.
Why it's wrong here
SSE-C would cause a different error (InvalidArgument), not AccessDenied.
- ✗
The EMR service role does not have permissions to write to the S3 bucket.
Why it's wrong here
The service role is used by EMR to manage resources; the actual data access uses the instance profile.
- ✓
The EMR cluster is not using a VPC endpoint for S3, so requests are denied by the bucket policy's VPC condition.
Why this is correct
The bucket policy restricts access to VPC, but since the Spark job runs on EMR, its requests originate from inside the VPC only if a VPC endpoint is used; otherwise, they come from public IPs.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The S3 bucket is configured with 'Bucket owner enforced' setting for ACLs, and the EMR cluster's account is not the bucket owner.
Why it's wrong here
Bucket owner enforced affects ACLs, not IAM policy evaluation; access is still controlled by bucket policy.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume the EMR service role (EMR_EC2_DefaultRole) is responsible for all S3 access, but in reality the instance profile (EC2 instance role) handles data plane operations, and the bucket policy's VPC condition is the key blocker when earlier stages succeed but final writes fail.
Detailed technical explanation
How to think about this question
S3 bucket policies with VPC conditions (e.g., `aws:SourceVpc` or `aws:SourceVpce`) evaluate the source IP or VPC endpoint ID of the request. When an EMR cluster writes to S3 without a VPC endpoint, the request originates from a public IP (even if the cluster is in a private subnet with a NAT gateway), which fails the condition. Using a Gateway VPC endpoint for S3 ensures traffic stays within the AWS network and matches the VPC condition, while an Interface endpoint uses a private IP and also satisfies the condition. This is a common misconfiguration when combining VPC-restricted bucket policies with EMR or other services that need direct S3 access.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Data Store Management — study guide chapter
Learn the concepts, then practise the questions
- →
Data Store Management practice questions
Targeted practice on this topic area only
- →
All DEA-C01 questions
1,786 questions across all exam domains
- →
AWS Certified Data Engineer Associate DEA-C01 study guide
Full concept coverage aligned to exam objectives
- →
DEA-C01 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related DEA-C01 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Data Ingestion and Transformation practice questions
Practise DEA-C01 questions linked to Data Ingestion and Transformation.
Data Operations and Support practice questions
Practise DEA-C01 questions linked to Data Operations and Support.
Data Security and Governance practice questions
Practise DEA-C01 questions linked to Data Security and Governance.
Data Store Management practice questions
Practise DEA-C01 questions linked to Data Store Management.
DEA-C01 fundamentals practice questions
Practise DEA-C01 questions linked to DEA-C01 fundamentals.
DEA-C01 scenario practice questions
Practise DEA-C01 questions linked to DEA-C01 scenario.
DEA-C01 troubleshooting practice questions
Practise DEA-C01 questions linked to DEA-C01 troubleshooting.
Practice this exam
Start a free DEA-C01 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this DEA-C01 question test?
Data Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The EMR cluster is not using a VPC endpoint for S3, so requests are denied by the bucket policy's VPC condition. — The bucket policy restricts access to requests originating from the VPC, typically using a condition like `aws:SourceVpc`. If the EMR cluster does not use a VPC endpoint for S3 (either Gateway or Interface endpoint), traffic from the cluster to S3 traverses the public internet and does not match the VPC condition, causing the `S3AccessDeniedException`. Earlier stages may succeed if they use cached data or different paths, but the final write fails because it hits the bucket policy check.
What should I do if I get this DEA-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 24, 2026
This DEA-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DEA-C01 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.