What is the purpose of the area {area-id} sham-link {source-address} {destination-address} cost {number} command?

A.
to create an OSPF virtual link between two CE routers

B.
to allow the customer sites to use the same OSPF area ID

C.
to enable optimized routing over the MPLS backbone when there is a direct backdoor link between two CE routers

D.
to allow the MPLS backbone to act as an OSPF Superbackbone

E.
to prevent routing loops when using OSPF as the CE-PE routing protocol

F.
to allow the customer sites to use area 0 as the OSPF area ID