How does in-memory caching improve the performance of applications in ElastiCache?

A.
It improves application performance by deleting the requests that do not contain frequently
accessed data.

B.
It improves application performance by implementing good database indexing strategies.

C.
It improves application performance by using a part of instance RAM for caching important data.

D.
It improves application performance by storing critical pieces of data in memory for low-latency
access.

Explanation:
In Amazon ElastiCache, in-memory caching improves application performance by storing critical
pieces of data in memory for low-latency access. Cached information may include the results of
I/O-intensive database queries or the results of computationally intensive calculations.
http://aws.amazon.com/elasticache/faqs/#g4