Question 1,025 of 1,755
Data EngineeringmediumMultiple SelectObjective-mapped

MLS-C01 Data Engineering Practice Question

This MLS-C01 practice question tests your understanding of data engineering. 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 engineer needs to transform and move 2 TB of data from an Amazon RDS for PostgreSQL instance to Amazon S3 daily. The transformation includes filtering, joining with data in S3, and aggregating. Which AWS services can be used together to accomplish this with minimal operational overhead? (Choose THREE.)

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Amazon S3

Amazon S3 is correct because it serves as the target storage location for the transformed data. The daily 2 TB output from the ETL pipeline must be stored durably and cost-effectively, and S3 provides the ideal object storage layer for this purpose, especially when combined with AWS Glue for the transformation logic.

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.

  • Amazon EMR

    Why it's wrong here

    EMR requires cluster management, increasing overhead.

  • Amazon Redshift

    Why it's wrong here

    Redshift is a data warehouse, not needed for this pipeline.

  • Amazon S3

    Why this is correct

    Target storage for transformed data.

    Related concept

    Read the scenario before looking for a memorised answer.

  • AWS Glue Data Catalog

    Why this is correct

    Stores metadata and schema information.

    Related concept

    Read the scenario before looking for a memorised answer.

  • AWS Glue

    Why this is correct

    Serverless ETL service to transform and move data.

    Related concept

    Read the scenario before looking for a memorised answer.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often assume Amazon EMR or Redshift are necessary for large-scale data processing, but AWS Glue's serverless Spark engine can handle 2 TB daily without any cluster management, making it the lower-overhead choice.

Detailed technical explanation

How to think about this question

AWS Glue is a serverless ETL service that can read from RDS for PostgreSQL via JDBC, join with data in S3 using Spark DataFrames, perform aggregations, and write results directly to S3 in formats like Parquet or ORC. The AWS Glue Data Catalog acts as a central metadata repository, enabling schema discovery and versioning without manual table definitions. This combination eliminates the need to manage any infrastructure, as Glue automatically scales resources based on the data volume.

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.

TExam Day Tips

  • 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.

Quick reference

AWS S3 Storage Class Comparison

Storage ClassMin DurationRetrievalUse Case
S3 StandardNoneImmediateFrequently accessed data
S3 Standard-IA30 daysImmediateInfrequent access, rapid retrieval
S3 One Zone-IA30 daysImmediateNon-critical infrequent data
S3 Intelligent-TieringNoneImmediate–hoursUnknown or changing access patterns
S3 Glacier Instant90 daysMillisecondsArchive with instant retrieval
S3 Glacier Flexible90 daysMinutes–hoursArchive, flexible retrieval
S3 Glacier Deep Archive180 daysHoursLong-term compliance archive

What to study next

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FAQ

Questions learners often ask

What does this MLS-C01 question test?

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: Amazon S3 — Amazon S3 is correct because it serves as the target storage location for the transformed data. The daily 2 TB output from the ETL pipeline must be stored durably and cost-effectively, and S3 provides the ideal object storage layer for this purpose, especially when combined with AWS Glue for the transformation logic.

What should I do if I get this MLS-C01 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jul 4, 2026

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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.