Mr.Cheng said that he would be punctual for the appointment,

Mr.Cheng said that he would be punctual for the appointment,___ he were late
A.but what if B.and what about C.so what D.how about
请问该选哪个?
punctual 准时,守时
appointment 约会

选A
what if...是“如果.的话怎么办?”的意思.
由于是假设,所以用虚拟语气.
what about和how about都是问对方的意见,或提议时用的.
so what?在口语中常用.可以理解为“然后呢?”“那又怎样?”,就是询问对方说此话的意图.如：
A：I met a trafic jam. (我路上塞车了.)
B: So what? （然后呢?/那又怎样?）
A: So I am late.(所以我迟到了)