How should the solution architect describe the XIV usage of SSD?

A storage array proposal needs to include the use of SSD. The solution architect proposes XIV.

How should the solution architect describe the XIV usage of SSD?
A . SSDs are utilized as a secondary read cache.
B . Performance improvements happen after a learning period.
C . SSDs require the customer to define data placement policies.
D . A separate tier of SSDs is implemented with automatic tiering.

Answer: A