Answer: Amazon S3 Standard

## Explanation **Correct Answer: C - Amazon S3 Standard** **Key Requirements Analysis:** 1. **Data volume**: 300 MB per month (very small amount) 2. **Data format**: JSON 3. **Accessibility**: Must be accessible in milliseconds if needed 4. **Retention**: 30 days 5. **Cost-effectiveness**: Most cost-effective solution **Option Analysis:** **A. Amazon OpenSearch Service (Amazon Elasticsearch Service)** - Designed for search and analytics, not primarily for backup/disaster recovery - More expensive than S3 for simple storage - Overkill for just storing 300 MB of JSON data - Not the most cost-effective option **B. Amazon S3 Glacier** - Designed for long-term archival storage - Has retrieval times ranging from minutes to hours (not milliseconds) - Retrieval costs apply when accessing data - Not suitable for millisecond accessibility requirement **C. Amazon S3 Standard** - **Millisecond access**: S3 provides millisecond access to objects - **Cost-effective**: For 300 MB per month, S3 Standard is very inexpensive - **Retention**: Can store data for 30 days easily - **JSON support**: Perfect for storing JSON files - **Durability**: 99.999999999% (11 9's) durability - **Availability**: 99.99% availability **D. Amazon RDS for PostgreSQL** - Relational database service, not designed for simple backup storage - More expensive than S3 for storage - Over-engineered for storing 300 MB of JSON backup data - Not cost-effective for this use case **Why S3 Standard is the best choice:** 1. **Cost**: S3 Standard storage costs are very low (~$0.023 per GB per month). For 300 MB, this is negligible. 2. **Performance**: Provides millisecond access to objects 3. **Simplicity**: Simple to implement as a backup target 4. **Lifecycle policies**: Can use S3 Lifecycle policies to automatically delete data after 30 days 5. **Durability**: Extremely durable storage **Alternative consideration**: For even more cost savings, S3 Standard-IA (Infrequent Access) could be considered, but given the small data volume and 30-day retention, S3 Standard is perfectly adequate and simpler. **Implementation approach**: - Store JSON files directly in S3 - Use S3 Lifecycle policy to automatically delete objects after 30 days - The analytics application can write directly to S3 or use AWS Backup service - Access is immediate when needed for disaster recovery

Author: LeetQuiz Editorial Team