A company manages an application that uses Amazon ElastiCache for Redis with two extra-large nodes spread across two different Availability Zones. The company's IT team discovers that the ElastiCache for Redis cluster has 75% freeable memory. The application must maintain high availability.
What is the MOST cost-effective way to resize the cluster?

A. Decrease the number of nodes in the ElastiCache for Redis cluster from 2 to 1.
B. Deploy a new ElastiCache for Redis cluster that uses large node types. Migrate the data from the original cluster to the new cluster. After the process is complete, shut down the original cluster.
C. Deploy a new ElastiCache for Redis cluster that uses large node types. Take a backup from the original cluster, and restore the backup in the new cluster. After the process is complete, shut down the original cluster.
D. Perform an online resizing for the ElastiCache for Redis cluster. Change the node types from extra-large nodes to large nodes.