DEA-C01 Data Ingestion and Transformation Practice Question
This DEA-C01 practice question tests your understanding of data ingestion and transformation. 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.
Refer to the exhibit. An IAM policy for an AWS Lambda function. The Lambda function is triggered by an S3 event (object created) and needs to read from a Kinesis stream. However, the function fails with access denied when trying to read from Kinesis. 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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The Kinesis stream is encrypted with a customer managed KMS key, and the Lambda function lacks kms:Decrypt permission
Option C is correct because when a Kinesis stream is encrypted with a customer managed KMS key, the Lambda function must have the `kms:Decrypt` permission on that key to read data from the stream. Without this permission, the Lambda function will receive an access denied error even if it has the necessary Kinesis actions (e.g., `kinesis:GetRecords`) allowed in its IAM policy. The S3 event trigger only invokes the function; it does not grant Kinesis access.
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 Lambda function is not in the same region as the Kinesis stream
Why it's wrong here
Cross-region access is allowed if permissions are correct.
✗
The Lambda function does not have permission to list S3 buckets
Why it's wrong here
The error is about Kinesis, not S3.
✓
The Kinesis stream is encrypted with a customer managed KMS key, and the Lambda function lacks kms:Decrypt permission
Why this is correct
If the stream uses SSE-KMS, Lambda needs kms:Decrypt on the key.
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 policy denies access to the Lambda function
Why it's wrong here
The error is about Kinesis, not S3.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The DEA-C01 exam often tests the interaction between Kinesis SSE-KMS and Lambda IAM permissions, trapping candidates who assume that Kinesis read permissions alone are sufficient without considering the KMS key policy.
Detailed technical explanation
How to think about this question
When a Kinesis stream uses server-side encryption with a customer managed KMS key (SSE-KMS), the Kinesis service calls KMS to decrypt the data on behalf of the consumer. The Lambda function's execution role must include a `kms:Decrypt` permission on the specific KMS key ARN; otherwise, KMS returns an access denied error, which Kinesis propagates as a `KMSAccessDeniedException`. This is a common pitfall because the IAM policy for Kinesis actions may be correctly configured, but the missing KMS permission causes the failure.
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.
Quick reference
AWS S3 Storage Class Comparison
Storage Class
Min Duration
Retrieval
Use Case
S3 Standard
None
Immediate
Frequently accessed data
S3 Standard-IA
30 days
Immediate
Infrequent access, rapid retrieval
S3 One Zone-IA
30 days
Immediate
Non-critical infrequent data
S3 Intelligent-Tiering
None
Immediate–hours
Unknown or changing access patterns
S3 Glacier Instant
90 days
Milliseconds
Archive with instant retrieval
S3 Glacier Flexible
90 days
Minutes–hours
Archive, flexible retrieval
S3 Glacier Deep Archive
180 days
Hours
Long-term compliance archive
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 Ingestion and Transformation — This question tests Data Ingestion and Transformation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The Kinesis stream is encrypted with a customer managed KMS key, and the Lambda function lacks kms:Decrypt permission — Option C is correct because when a Kinesis stream is encrypted with a customer managed KMS key, the Lambda function must have the `kms:Decrypt` permission on that key to read data from the stream. Without this permission, the Lambda function will receive an access denied error even if it has the necessary Kinesis actions (e.g., `kinesis:GetRecords`) allowed in its IAM policy. The S3 event trigger only invokes the function; it does not grant Kinesis access.
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.
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Question Discussion
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