In MPLS VPN, where must MP-BGP peering be configured?

A.
in all CE routers within a VPN community

B.
in all CE routers across a VPN community

C.
in all PE routers within a VPN community

D.
in all PE routers across a VPN community

E.
in all PE and CE routers within a VPN community

F.
in all PE and CE routers across a VPN community