BGP best route selection process is based on what ？（）

A.It prevents message looping，Session Advertisement（SA）messages must be RPF checked
B.RPF check should be done against the route to the Rendez-vous Point of the corresponding PIM-SM domain，which originated the SA
C.RPF checking Session Advertisement（SA）messages will cause message looping
D.RPF check should be done against the route to the source S of the corresponding PIM-SM domain

A.LDP and RSVP
B.RSVP and CEF
C.CEF and the FIB table
D.UDP and IP
E.A and B

A.LSA type 1
B.LSA type 2
C.LSA type 7
D.LSA type 3
E.LSA type 9
F.LSA type 5