— When can I see you Mr Black? Three o’clock this afternoon?— Oh no. I a meeting then.

问题补充：

— When can I see you, Mr Black? Three o’clock this afternoon?

— Oh, no. I a meeting then.

A. will have

B. will be having

C. am having

D. have

答案：

A. will have

(答案→)B. will be having

C. am having

D. have

解析：此处用将来进行时强调在将来某个时间正在进行的动作。故选B。