This MLS-C01 practice question tests your understanding of exploratory data analysis. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: amazon Athena. 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 data scientist runs the above AWS CLI command and gets the output. The object size is 1 GB. They try to open the CSV file in Amazon Athena but get an error. 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 file format is not supported by Athena
Why wrong: Athena supports CSV.
The file exceeds the maximum CSV file size that Athena can query without partitioning
Athena has a 100 MB limit for CSV files when not partitioned.
The file is not compressed with gzip
Why wrong: Athena supports gzip compression.
The file is too large for Athena to query at all
Why wrong: Athena can query larger files if partitioned or using other formats.
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 file exceeds the maximum CSV file size that Athena can query without partitioning
Option B is correct because Amazon Athena has a default limit of 100 MB per CSV file when querying without partitioning. A 1 GB file exceeds this limit, causing an error. Option A is wrong because CSV is a supported file format in Athena. Option C is wrong while gzip compression is supported, it is not required; the issue is file size, not compression. Option D is wrong because Athena can query large files, but only if they are properly partitioned or if the file size is within the per-file limit.
Key principle: Amazon Athena
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The file format is not supported by Athena
Why it's wrong here
Athena supports CSV.
The file exceeds the maximum CSV file size that Athena can query without partitioning
Why this is correct
Athena has a 100 MB limit for CSV files when not partitioned.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Amazon Athena
The file is not compressed with gzip
Why it's wrong here
Athena supports gzip compression.
The file is too large for Athena to query at all
Why it's wrong here
Athena can query larger files if partitioned or using other formats.
Common exam traps
Athena's 100 MB per-file limit for CSV queries without partitioning is often overlooked; candidates may assume the file is too large overall, but partitioning allows much larger datasets.
Detailed technical explanation
Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.
Key takeaway
Amazon Athena
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
Review amazon Athena, then practise related MLS-C01 questions on the same topic to reinforce the concept.
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FAQ
Exploratory Data Analysis — This question tests Exploratory Data Analysis — Amazon Athena.
The correct answer is: The file exceeds the maximum CSV file size that Athena can query without partitioning — Option B is correct because Amazon Athena has a default limit of 100 MB per CSV file when querying without partitioning. A 1 GB file exceeds this limit, causing an error. Option A is wrong because CSV is a supported file format in Athena. Option C is wrong while gzip compression is supported, it is not required; the issue is file size, not compression. Option D is wrong because Athena can query large files, but only if they are properly partitioned or if the file size is within the per-file limit.
Review amazon Athena, then practise related MLS-C01 questions on the same topic to reinforce the concept.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Amazon Athena
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Last reviewed: Jun 20, 2026
This MLS-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 MLS-C01 exam.
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