The answer is data format and compression support, query performance and cost, and integration with the ML pipeline. These three factors are critical because Amazon S3 excels as a cost-effective, scalable object store for raw or semi-structured data like Parquet and CSV, while Amazon Redshift is optimized for high-performance SQL analytics on structured, columnar data with automatic compression. On the AWS Certified Machine Learning Specialty MLS-C01 exam, this question tests your ability to distinguish storage services based on workload patterns—S3 for data lakes and feature stores, Redshift for transformed, query-heavy datasets. A common trap is assuming security or retention policies drive the choice, but both services support encryption and lifecycle rules; the real differentiator is how the data will be accessed during training and inference. Memory tip: think “S3 for source, Redshift for sorted”—if you need fast aggregations or joins on structured data, choose Redshift; for flexible, cheap storage of any format, choose S3.
MLS-C01 Data Engineering Practice Question
This MLS-C01 practice question tests your understanding of data engineering. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Which THREE factors should a data engineer consider when choosing between Amazon S3 and Amazon Redshift for storing large datasets used for machine learning? (Choose 3.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Query performance and latency requirements
Options A, C, and E are key considerations. Option B is about data retention, not storage choice. Option D is about security, which both services support.
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.
✓
Query performance and latency requirements
Why this is correct
Redshift provides fast SQL analytics; S3 queries are slower.
Related concept
Read the scenario before looking for a memorised answer.
S3 is cheaper for storage; Redshift is more expensive but includes compute.
Related concept
Read the scenario before looking for a memorised answer.
✓
Data format and compression support
Why this is correct
S3 supports any format; Redshift optimizes columnar formats.
Related concept
Read the scenario before looking for a memorised answer.
✗
Data retention policies
Why it's wrong here
Both services support lifecycle policies; not a differentiator.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
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.
Data Engineering — This question tests Data Engineering — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Query performance and latency requirements — Options A, C, and E are key considerations. Option B is about data retention, not storage choice. Option D is about security, which both services support.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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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.
Question Discussion
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