A company uses Amazon ElastiCache (Redis OSS) to cache application data.

Amazon ElastiCache for Redis supports Multi-AZ replication groups, which provide high availability by automatically promoting a replica in another Availability Zone if the primary node fails. This architecture significantly reduces recovery time because failover occurs automatically without manual intervention.

Creating a read replica in a second AZ ensures redundancy and resilience against AZ-level failures. Enabling Multi-AZ allows Redis to maintain availability during infrastructure issues or maintenance events.

Option A removes persistence and high availability features. Options B and D rely on backups, which increase RTO because restore operations take time and require manual steps.

Therefore, Multi-AZ Redis with replicas provides the best combination of resilience and minimal RTO.