what must be implemented to enable Layer 3 MPLS VPN services?

Within the service provider IP/MPLS core network, what must be implemented to enable Layer 3
MPLS VPN services?

A.
IS-IS or OSPF on all the PE and P routers

B.
MP-BGP between the PE routers

C.
RSVP on all the PE and P routers

D.
targeted LDP between the PE routers

E.
LDP between the CE and PE routers