SAP-C02 Design for New Solutions Practice Question
A company is designing a serverless application using AWS Lambda. The application needs to store and retrieve JSON documents. The company wants the lowest cost for infrequent access. Which data store should be used?
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 DynamoDB (on-demand)
Amazon DynamoDB with on-demand capacity is serverless and cost-effective for infrequent access. Option A is wrong because Amazon RDS for MySQL is relational and not serverless, and would require provisioning and scaling, leading to higher cost. Option B is wrong because Amazon S3 Standard is not ideal for small JSON documents and has higher cost for frequent updates or retrieval. Option C is wrong because Amazon ElastiCache for Redis is a cache, not a durable store.
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 RDS for MySQL
Why it's wrong here
Amazon RDS for MySQL is relational and not serverless, and would require provisioning and scaling, leading to higher cost for infrequent access.
- ✗
Amazon S3 Standard
Why it's wrong here
Amazon S3 Standard is not ideal for small JSON documents and has higher cost for frequent updates or retrieval of individual items; also, it is not a database for complex queries.
- ✗
Amazon ElastiCache for Redis
Why it's wrong here
Amazon ElastiCache for Redis is a cache, not a durable store; data can be lost on failure, and it is not designed for long-term storage.
- ✓
Amazon DynamoDB (on-demand)
Why this is correct
Amazon DynamoDB with on-demand capacity is serverless, scales automatically, and is cost-effective for infrequent access with no minimum charges.
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 SAP-C02 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 SAP-C02 exam.