Question 313 of 1,672
MLS-C01 Data Engineering Practice Question
Exhibit
Refer to the exhibit.
{
"Records": [
{
"eventVersion": "2.1",
"eventSource": "aws:s3",
"awsRegion": "us-east-1",
"eventName": "ObjectCreated:Put",
"s3": {
"bucket": {
"name": "my-bucket"
},
"object": {
"key": "data/sample.csv"
}
}
}
]
}A Lambda function is triggered by S3 events. The event payload shown in the exhibit is received by the Lambda function. The function is supposed to process the CSV file and load it into DynamoDB. However, the function fails because it cannot read the file. What is the MOST likely cause?
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
✓
The Lambda function's IAM role does not have s3:GetObject permission
The Lambda function cannot read the file from S3 because its IAM role does not have the s3:GetObject permission. Option A is wrong because the failure is not due to DynamoDB write permissions; the function fails before writing. Option C is wrong because the S3 bucket exists, as indicated by the event triggering. Option D is wrong because the event notification is correctly configured to trigger the Lambda function, as evidenced by the function receiving the event.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The Lambda function lacks DynamoDB write permissions
Why it's wrong here
The error is about reading the file, not writing to DynamoDB.
- ✓
The Lambda function's IAM role does not have s3:GetObject permission
Why this is correct
Without read permission, the function cannot access the S3 object.
- ✗
The S3 bucket does not exist
Why it's wrong here
The event would not have been generated if the bucket didn't exist.
- ✗
The S3 event notification is misconfigured
Why it's wrong here
The event notification is correctly sending the payload.
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 |
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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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