Which option is the most likely reason for the problem?

You have recently deployed an access switch with two fiber cables that connect it to a distribution switch in EtherChannel mode. Soon after it booted up, one of the uplink ports to the distribution switch was error-disabled.

Which option is the most likely reason for the problem?
A . The port-channel detected an inconsistent configuration
B . The switch is operating in UDLD aggressive mode and it failed to receive a UDLD message from the peer
C . spanning tree detected a loop
D . The switch is operating in UDLD normal mode and it failed to receive a UDLD message from the peer

Answer: A