单选题 The reason why I can't attend the ball is ______ I'm to see off one of my friends at the railway station.
A) for C) why
B) because D) that

【正确答案】 D
【答案解析】the reason why…is that…中的that引导表语从句，后接理由。句意：我不能参加舞会，我得去火车站接一位朋友。