How are customer routes exchanged across the P-network?

How are customer routes exchanged across the P-network?

A.
LDP is used to exchange customer routes across the P-network-.

B.
IBGP is used to exchange customer routes across the P-network.

C.
OSPF is used to exchange customer routes across the P-network.

D.
MP-BGP is used to exchange customer routes across the P-network.

Explanation:

It must be D, OSPF can only be used as in IGP within P network and does not have the
capabilities to carry any customer route.