—May I remind you that a Mr. Wang is waiting outside sir?—Oh that’s right. I about it.A

问题补充：

—May I remind you that a Mr. Wang is waiting outside, sir?

—Oh, that’s right. I about it.

A. forget

B. had forgotten

C. forgot

D. have forgotten

答案：

A. forget

B. had forgotten

(答案→)C. forgot

D. have forgotten

解析：forget是发生在第一个人提醒（remind）之前，表示瞬间的过去。故选C