Implementing H-VPLS instead of VPLS reduces which requirement?

A.
having a full mesh of PWs between all the PE routers in the service provider MPLS core

B.
having a full mesh of PWs between all the UPE routers

C.
having to implement QinQ tagging between the UPE and the NPE

D.
having to implement MPLS LDP between the UPE and the NPE

E.
the overhead of using BGP or LDP autodiscovery

Explanation: