Which two conditions could explain the issue?

An administrator is having a problem configuring Storage I/O Control on a Datastore.
Which two conditions could explain the issue? (Choose two.)

A.
A host is running ESXi 4.0.

B.
An ESXi host does not have appropriate licensing.

C.
The vCenter Server version is 5.0.

D.
The vCenter Server License is Standard.