The answer is that the IAM policy is missing the s3:PutObject permission, which is required for Athena to write query results to an S3 bucket. Even though the policy grants s3:GetObject and s3:ListBucket for reading the source data, Athena must also write the output of every query—such as CSV or Parquet files—to a designated S3 output location, and without s3:PutObject on that bucket, the query will fail with a permissions error. On the AWS Certified Machine Learning Specialty MLS-C01 exam, this tests your understanding that Athena is fundamentally a serverless query service that requires both read and write access to S3, a detail often overlooked when focusing only on data access. A common trap is assuming that read permissions alone suffice, but the exam expects you to remember that query results must be written somewhere. Memory tip: “Athena reads data, but it also writes results—so always check for PutObject on the output bucket.”
MLS-C01 Exploratory Data Analysis Practice Question
This MLS-C01 practice question tests your understanding of exploratory data analysis. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 data scientist is unable to query a table in Amazon Athena that is located in the 'my-data-bucket' S3 bucket. The IAM policy shown is attached to the scientist's role. What is the most likely reason for 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 policy does not allow s3:PutObject to write query results to an S3 bucket.
Athena queries also require permission to write query results to a S3 bucket, typically specified as 's3:PutObject' on an output location. The policy lacks that permission. Option A is wrong because the policy allows s3:GetObject and s3:ListBucket. Option C is wrong because athena:StartQueryExecution is allowed. Option D is wrong because there is no encryption restriction in the policy.
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 policy does not allow decrypting data encrypted with AWS KMS.
Why it's wrong here
No KMS actions are mentioned, but the policy does not prevent decryption either; the error is likely missing S3 write.
✗
The policy does not allow athena:StartQueryExecution.
Why it's wrong here
athena:StartQueryExecution is allowed.
✗
The policy does not allow s3:GetObject on the bucket.
Why it's wrong here
s3:GetObject is allowed.
✓
The policy does not allow s3:PutObject to write query results to an S3 bucket.
Why this is correct
Athena writes results to S3, requiring s3:PutObject.
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.
Common exam traps
Common exam trap: answer the scenario, not the keyword
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
How to think about this question
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.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 MLS-C01 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.
Exploratory Data Analysis — This question tests Exploratory Data Analysis — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The policy does not allow s3:PutObject to write query results to an S3 bucket. — Athena queries also require permission to write query results to a S3 bucket, typically specified as 's3:PutObject' on an output location. The policy lacks that permission. Option A is wrong because the policy allows s3:GetObject and s3:ListBucket. Option C is wrong because athena:StartQueryExecution is allowed. Option D is wrong because there is no encryption restriction in the policy.
What should I do if I get this MLS-C01 question wrong?
Identify which MLS-C01 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.
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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