Given this "debug isdn q921" output, what is the problem with the PRI?

exams 350-801 V7 350-801 exam 0 Comments

Refer to exhibit.

Given this "debug isdn q921" output, what is the problem with the PRI?
A . Nothing, the PRI is sending keepalives.
B . Layer 2 is down on the controller.
C . PRI does not have an IP address configured on the interface.
D . Layer 1 is down on the controller.

Answer: B