What two conditions would cause this behavior?

An administrator has deployed NSX in an environment containing a mix of vSphere 5 hosts.
The implementation includes the Distributed Firewall Service, but the administrator finds
that rules are not being applied to all affected virtual machines. What two conditions would
cause this behavior? (Choose two.)

A.
Some hosts have not been prepared for NSX.

B.
Only ESXi 5.5 and later hosts can push the rules to the virtual machines.

C.
Only ESXi 5.1 and later hosts can push the rules to the virtual machines.

D.
Some hosts are blocking the port used for rule distribution.