I only know it is a ____ distance away from here,  but I don’t know ____ the distance exactly is.

A great,  how far  B great,  what      C far,  how far   D far,  what         

在电缆布置上，全自动车钩内设置了联挂牵引、停车制动施加及释放、广播、司机室通信等列车导线。