Which statement about the BFD-BGP Multihop Client Support and cBit feature is true? 

Answer options:

A. BFD cBit feature replaces the BGP graceful restart and the BGP fast-failover features by keeping stale routers in the RIB when a failure occurs on the control plane.
B. The cBit in BFD determines if the BFD session failure is independent or dependent of the control plane.
C. BFD cBit improves the BGP convergence and response time to adjacency changes with BGP neighbors; in any event of adjacency changes, the session is deactivated in the next BGP scanning interval.
D. BFD cBit identifies VPNv4 and VPVn6 in a multihomed to avoid purging prefixes in an event of link failure when a backup link exists and is installed already in the RIB/FIB.

B

Reference: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/15-s/irg-15-s-book/irg-multihop-cbit.pdf