MLS-C01 Data Engineering Practice Question
A company uses Amazon Kinesis Data Firehose to deliver streaming data to Amazon S3. The data contains personally identifiable information (PII) that must be redacted before storage. Which AWS service can be integrated with Kinesis Data Firehose to transform the data in real time?
⚠ Common exam trap
It's easy for candidates to confuse Kinesis Data Analytics for transformation, but it is designed for real-time analytics and pattern detection, not for inline record-by-record data masking or redaction within a Firehose delivery stream.
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
✓
AWS Lambda
AWS Lambda can be integrated as a data transformation function within a Kinesis Data Firehose delivery stream. When Firehose receives incoming records, it can invoke a Lambda function synchronously to process each batch of data, allowing you to redact PII fields in real time before the data is written to Amazon S3.
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 Athena
Why it's wrong here
Athena is an interactive query service, not for real-time transformation.
- ✗
Amazon Kinesis Data Analytics
Why it's wrong here
Data Analytics is for running SQL on streams, not for record transformation.
- ✗
Amazon EMR
Why it's wrong here
EMR is not designed for inline transformations within Firehose.
- ✓
AWS Lambda
Why this is correct
Lambda can be invoked by Firehose to transform records in real time.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.