A solution architect would like to implement a caching solution for an application. The application is read-heavy performing frequent read operations. The application load is very unpredictable. So the solution architect would like to be able to horizontally scale the caching system up and down as required, while keeping the infrastructure costs minimal. What is the optimal solution to this problem?

Answer options:

A.Deploy Amazon ElastiCache for Redis (Cluster Mode Disabled) cluster.
B.Deploy Amazon ElastiCache for Redis (Cluster Mode Enabled) cluster.
C.Deploy Amazon DAX cluster.
D.Implement Write-Through caching strategy.

Answer: A
Option A is CORRECT because ElastiCache for Redis (Cluster Mode Disabled) clusters support scaling up or down of read capacity by creating or deleting read replicas within the cluster.
Option B is incorrect because horizontally scaling ElastiCache for Redis (Cluster Mode Enabled) clusters can be a complex activity as it can require re-sharding of the clusters. Therefore, this is not the ideal solution.
Option C is incorrect because Amazon DAX is a caching solution specific to DynamoDB.Option D is incorrect because Write-Through caching strategy is related to the consistency of data in cache in relation to the base source database. It is not relevant to the scenario.
Reference:
https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/Replication.Redis-RedisCluster.html