A user has no network connectivity. A check of the associated port indicates that the interface is up，the line protocol is down. Which item would most likely cause this problem？（）

A.Cisco
B.ANSI - Annex D
C.Q.931 - Annex B
D.Q.933 - Annex A

A.EBGP multihop will need to be configured for this to work.
B.This should work with normal BGP peering，with no additional configuration on the BGP speakers or the firewall.
C.The BGP protocol port must be opened on the firewall
D.There is no way to make BGP work across a firewall.