What is the possible reason for the BSC handover failure in this cell?

The success rate of outbound BSC handover in a certain cell is relatively low, and the number of outbound handover attempts between BSCs in the traffic statistics is almost equal to the number of outbound handovers between BSCs.

What is the possible reason for the BSC handover failure in this cell?
A . The target cell is congested
B. The CGI of the target cell is not defined in MS C
C. The carrier frequency hardware of the target cell is faulty, and the TCH channel cannot be activated
D. The wireless interface of the target cell has severe interference

Answer: D