Which label protocol should the backbone carrier use to provide the proper connectivity that the ISP_A requires?

A backbone carrier is approached by an ISP_A which provides L3VPN services. The ISP_A requires MPLS VPN services from the backbone carrier to establish connectivity between the two POPs of the ISP_A.

Which label protocol should the backbone carrier use to provide the proper connectivity that the ISP_A requires?

A. L2TPv3

B. L2TPv2

C. LDP

D. GRE

E. mGRE

F. BGP

Answer: A