What is the purpose of the flash cache option in integrated caching?

A.
To completely wipe a cache group when the targeted selector is hit in the cache

B.
To answer the client request without checking if the object has expired, objects are
checked periodically instead

C.
To queue simultaneous requests of an object and answer all with the same response
from the server

D.
To use the flash memory for storage for a specific cache group to improve performance