Which two of the following statements are true about VPIM? (Choose two)

A.
VPIM is used to exchange email messages between different voice-mail systems.

B.
voice-mail systems that are using VPIM must have unique extensions.

C.
VPIM must use a location ID for each voice-mail system.

D.
VPIM must be used when internetworking Cisco Unity Connection and Cisco Unity Express.

E.
VPIM users cannot be regular voice-mail users.

F.
VPIM message use a similar format to SIP SDP messages, as defined in RFC 3281.