How many drives of AC2 can be shared in Zone A?

Refer to the exhibit.

An EMC NetWorker customer has two data zones, A and B, with autochanger AC1 and AC2, respectively, with four drives each. AC1 is configured as a dedicated autochanger and AC2 is configured as a shared autochanger. Two drives of AC2 are statically assigned.

How many drives of AC2 can be shared in Zone A?
A . 2
B . 4
C . 0
D . 6

Answer: C