Refer to the exhibit. 
Which explanation would be a reason for the line protocol being down?
A.
The clock rate (1544 Kbit) is set too high on serial 0/0/0.
B.
The cable to Serial 0/0/0 is disconnected.
C.
The remote end is not configured for PPP encapsulation.
D.
Serial 0/0/0 requires an IP address for the line protocol to transition to up.
Explanation: