单项选择题

A. It is configured and functioning correctly as an OSPF internal router.
B. It is configured and functioning correc tly as an ABR attached to stub area 4.
C. It is configured and functioning correctly as an ASBR attached to external area 4.
D. It is configured and functioning correctly as an ABR attached to totally stubby area 4.
E. It is not configured correctly to  function as specified.