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 retail company stores customer transaction data in an Amazon S3 bucket. The data is encrypted using server-side encryption with AWS KMS (SSE-KMS). The company uses an IAM role to allow an Amazon Athena query service to read the data. The data engineer creates a new Athena workgroup and attempts to run a query on the S3 bucket. The query fails with an access denied error. The IAM role has permissions to decrypt the KMS key and read from the bucket. The engineer checks the S3 bucket policy and finds that it does not explicitly allow access. What is the most likely cause of the failure?
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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The S3 bucket policy does not grant the required permissions to the Athena service principal.
Option D is correct because although the IAM role has permissions, the S3 bucket policy might explicitly deny access or not grant access to the Athena service. Option A is wrong because the IAM role has encryption permissions. Option B is wrong because cross-account access is not mentioned; the role is in the same account. Option C is wrong because Athena can query encrypted data with proper permissions.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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 is in a different AWS account than the Athena workgroup.
Why it's wrong here
There is no mention of cross-account; the role is likely in the same account.
✓
The S3 bucket policy does not grant the required permissions to the Athena service principal.
Why this is correct
The S3 bucket policy must explicitly allow the Athena service or the IAM role to access the bucket.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Standard ACLs match source addresses.
✗
The IAM role does not have permission to use the KMS key for encryption operations.
Why it's wrong here
The role has decrypt permissions, which is sufficient for reading.
✗
Athena does not support querying data encrypted with SSE-KMS.
Why it's wrong here
Athena supports SSE-KMS encrypted data.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DEA-C01 ACL questions on filtering logic and placement.
Data Store Management — This question tests Data Store Management — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: The S3 bucket policy does not grant the required permissions to the Athena service principal. — Option D is correct because although the IAM role has permissions, the S3 bucket policy might explicitly deny access or not grant access to the Athena service. Option A is wrong because the IAM role has encryption permissions. Option B is wrong because cross-account access is not mentioned; the role is in the same account. Option C is wrong because Athena can query encrypted data with proper permissions.
What should I do if I get this DEA-C01 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DEA-C01 ACL questions on filtering logic and placement.
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?
Standard ACLs match source addresses.
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 →
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.
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.