which VLAN?

You are setting up VLANs for integration with IP telephony. Cisco Unity must reside on which VLAN?

A.
on the same VLAN as the Cisco Unified CallManager

B.
on the same VLAN as the messaging servers

C.
In a voice-mail-only environment on the voice VLAN, in Cisco Unity Unified Messaging it does not matter.

D.
The voice VLAN is preferable, but not mandatory.