Refer to the above graphic. Switch A, the root bridge, is connected directly to Switch B over link L1
and to Switch C over link L2. The Layer 2 LAN interface on Switch C that is connected directly to
Switch B is in the blocking state. If Switch C detects a link failure on the currently active link L2 on
the root port, which spanning tree enhancement will allow Switch C to unblock the blocked port
and transition it to forwarding without going through the listening and learning states?

A.
UplinkFast

B.
rapid spanning tree

C.
BackboneFast

D.
PortFast