A solutions architect must design a highly available Amazon ElastiCache for Redis solution that prevents performance degradation and data loss locally and within an AWS Region. The solution must provide high availability at both the node and Region levels. Which solution meets these requirements?

The correct solution is to use Multi-AZ Redis replication groups with shards that contain multiple nodes. This configuration provides high availability at both the node and Region levels. Multi-AZ ensures automatic failover to a replica in a different Availability Zone if the primary node fails, preventing data loss and minimizing downtime within a Region. Sharding (clustering) distributes data across multiple primary nodes, each with its own replicas, preventing performance degradation by scaling horizontally and improving resilience. Incorrect options: Redis shards with AOF turned on primarily address data durability for individual nodes, not high availability across AZs or Regions, nor does it inherently prevent performance degradation from a single point of failure. A Multi-AZ Redis cluster with more than one read replica in the replication group is a good start, but the term "shards that contain multiple nodes" (implying a clustered setup) is more explicit about horizontal scaling for performance and resilience across multiple primary nodes. Redis shards with Auto Scaling turned on is not a native ElastiCache for Redis feature for node scaling; ElastiCache scales by adding or removing replicas or shards manually or through API calls, not traditional Auto Scaling.