What is an accurate statement about vSphere Fault Tolerant secondary virtual machines?

What is an accurate statement about vSphere Fault Tolerant secondary virtual machines?

A.
Cannot be stored on an NFS datastore

B.
Created on the same host as the primary

C.
Can prevent other virtual machines from powering up.

D.
Can be used for load balancing

Explanation:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=display
KC&externalId=1013428