While these different forms of greetings and customs might seem strange to you, remember ________ you consider normal probably seems equally strange to others.[ ]

A. that

B. what

C. which

D. when

车站一端有两个及其以上列车运行方向，办理闭塞（预告）及下达接发车命令时，应以线名或邻站名区别方向。