Standard OSPF-BGP redistribution results in OSPF routes that are passing though an MPLS VPN are inserted into the receiving sites rote tables as external routes. This makes stub areas and route summarization hard to implement.
How does an MPLS VPN overcome this problem?

A.
It uses well known RD’s for the different route types.

B.
Route types are allocated to each route in the router ospf configuration.

C.
It used BGP extended communities to propagate the OSPF route type.

D.
It used the BGP MED to propagate OSPF route type.