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.