单项选择题

A. The ASBR route - maps are basically useless, because there are no deny prefix - lists.
B. LSA Type 5s wil l not be received by the ABR from the ASBR.
C. The OSPF backbone will not learn any RFC 1918 addresses.
D. The matched prefix - list addresses will be given a metric of 255, which is essentially unreachable.