The winner of the race is tall and thin; he ___be my friend, Mike, who is short and fat.

A．might

B．mustn't

C．can't

D．should

LKJ与平面灯显配合使用进行调车作业时，在运行中接收到“五车”信号以后，列车走行20米后，限速变为（）km/h。