What is true about OSPF running between PE and CE routers?

What is true about OSPF running between PE and CE routers?

A.
Extra configuration is required to pass the OSPF route attributes from OSPF to MP-BGP.

B.
OSPF route attributes are carried as extended BGP attributes into MP-BGP.

C.
Extra configuration is required to pass the OSPF route attributes from MP-BGP to OSPF.

D.
Routes redistributed from MP-BGP to OSPF automatically maintain OSPF route attributes.

Explanation: