Quick Answer
The answer is that the service role lacks the s3:GetObject permission on the source bucket. This is the most likely cause because when CodeBuild attempts to download source code from an S3 bucket, it acts through an IAM service role, and that role must explicitly include the s3:GetObject action for the source bucket’s objects. Without this permission, the build process receives an Access Denied error, even if the bucket policy or other permissions appear correct. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of how CodeBuild’s service role interacts with S3 as a source type, and it’s a common trap to overlook the specific object-level permission in favor of broader bucket-level actions. A useful memory tip is “GetObject to get the object” — the service role needs the GetObject action on the source bucket’s objects, not just ListBucket or PutObject.
This DOP-C02 practice question tests your understanding of sdlc automation. 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. A DevOps engineer runs the above commands. The build project 'my-project' uses an S3 bucket as source and another S3 bucket for artifacts. The build fails with an 'Access Denied' error when trying to download the source code. 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.
The encryption key is a KMS key that the role cannot access
Why wrong: The key is the default S3 key, not a custom KMS.
The service role does not have s3:GetObject permission on the source bucket
The role needs GetObject to download the source.
The source type is S3, but the project expects CodeCommit
Why wrong: The source type is correctly S3.
The source location is incorrect
Why wrong: The location appears valid.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The service role does not have s3:GetObject permission on the source bucket
Option B is correct because the service role must have s3:GetObject permission on the source bucket. Option A is incorrect because the source type is S3, not CodeCommit. Option C is incorrect because the encryption key is the default S3 key, not a custom KMS key. Option D is incorrect because the source bucket is specified.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The encryption key is a KMS key that the role cannot access
Why it's wrong here
The key is the default S3 key, not a custom KMS.
The service role does not have s3:GetObject permission on the source bucket
Why this is correct
The role needs GetObject to download the source.
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 source type is S3, but the project expects CodeCommit
Why it's wrong here
The source type is correctly S3.
The source location is incorrect
Why it's wrong here
The location appears valid.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
Identify which DOP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
SDLC Automation — This question tests SDLC Automation — Read the scenario before looking for a memorised answer..
The correct answer is: The service role does not have s3:GetObject permission on the source bucket — Option B is correct because the service role must have s3:GetObject permission on the source bucket. Option A is incorrect because the source type is S3, not CodeCommit. Option C is incorrect because the encryption key is the default S3 key, not a custom KMS key. Option D is incorrect because the source bucket is specified.
Identify which DOP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 20, 2026
This DOP-C02 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 DOP-C02 exam.
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