What is the likely reason for this failure?

An administrator is attempting to enable Storage I/O Control on a datastore, but it is failing.
What is the likely reason for this failure?
A. The host is connected to a datastore is running on ESX 4.0.
B. The host is connected to a Fibre Channel storage array.
C. The datastore has multiple extents.
D. The datastore is managed by a single vCenter Server.