The answer is AWS Lambda triggered by an S3 event, because this service is purpose-built for event-driven, real-time file processing without managing servers. When a CSV file lands in an S3 bucket, the S3 event notification invokes the Lambda function, which can use libraries like PyArrow or Pandas to read the CSV, convert it to the columnar Parquet format, and write it back to S3—all within seconds of the file arrival. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of serverless event-driven architectures versus batch or heavy compute services; a common trap is choosing AWS Glue, which is ideal for scheduled or complex ETL jobs but adds startup latency and cost for simple per-file conversions. Remember the memory tip: “Lambda for landing, Glue for planning”—if the trigger is an S3 event, think Lambda first.
DEA-C01 Data Ingestion and Transformation Practice Question
This DEA-C01 practice question tests your understanding of data ingestion and transformation. 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.
A data engineering team needs to transform CSV files to Parquet format after they land in an S3 bucket. The transformation should be triggered automatically as soon as a new file arrives. Which AWS service is best suited for this task?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
AWS Lambda function triggered by S3 event
Option D is correct because AWS Lambda can be triggered by S3 events and convert files to Parquet using libraries like PyArrow. Option A (AWS Glue) is better for scheduled jobs, not event-driven. Option B (Amazon EMR) is overkill. Option C (AWS Batch) is for compute jobs but adds latency.
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.
✗
AWS Batch job submitted by S3 event
Why it's wrong here
AWS Batch has higher startup latency compared to Lambda.
✗
Amazon EMR cluster running continuously
Why it's wrong here
Running a persistent cluster is costly and inefficient for sporadic file arrivals.
✓
AWS Lambda function triggered by S3 event
Why this is correct
Lambda can be triggered immediately on S3 PUT events and perform the transformation.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
AWS Glue ETL job scheduled every 5 minutes
Why it's wrong here
Scheduled jobs introduce latency; Lambda provides near real-time trigger.
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 DEA-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 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: AWS Lambda function triggered by S3 event — Option D is correct because AWS Lambda can be triggered by S3 events and convert files to Parquet using libraries like PyArrow. Option A (AWS Glue) is better for scheduled jobs, not event-driven. Option B (Amazon EMR) is overkill. Option C (AWS Batch) is for compute jobs but adds latency.
What should I do if I get this DEA-C01 question wrong?
Identify which DEA-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: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This DEA-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 DEA-C01 exam.
Question Discussion
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