For infrequent or ad hoc querying of log data, Amazon S3 + Amazon Athena provides the most cost-effective, serverless, and scalable analytics solution.
From AWS Documentation:
“Amazon Athena is an interactive query service that makes it easy to analyze data in Amazon S3 using standard SQL. Athena is serverless, so there is no infrastructure to manage, and you pay only for the queries that you run.”
(Source: Amazon Athena User Guide)
Why A is correct:
Amazon S3 offers durable, scalable, and cost-efficient storage.
Athena allows SQL-based querying on structured or semi-structured data like logs.
No need to provision or manage infrastructure.
Ideal for occasional querying at low cost.
Why the others are not optimal:
Option B: OpenSearch adds cost and is best for frequent, low-latency log querying.
Option C: RDS is not optimized for large-scale write-heavy log ingestion and costs more.
Option D: CloudWatch Logs is suitable for real-time monitoring, not for long-term storage and analytics of large log volumes.
[References:, Amazon Athena User Guide, AWS Well-Architected Framework – Cost Optimization Pillar, Amazon S3 Storage Classes and Pricing Guide, , , ]