From the above GK log, we can see that the possible reasons for the call failure are?

08:08:01 ARJ sendto [(61.131.13.141:1719)] [Caller] [59512724] [(61.131.13.141:1720)] [Callee][59522000051] [[Ox0000006derr_call callee_offline]

From the above GK log, we can see that the possible reasons for the call failure are?
A . The called person is offline
B . The called person is busy
C . Insufficient call bandwidth
D . Capability negotiation failed

Answer: A