When about the source of his income he hesitated for a moment obviously not willing to

问题补充：

When about the source of his income, he hesitated for a moment, obviously not willing to give us a direct answer.

A. asked

B. asking

C. being asked

D. having asked

答案：

(答案→)A. asked

B. asking

C. being asked

D. having asked

解析：考查状语从句的省略。当从句主语与主句主语一致，并且从句主语后动词为be动词时，可以省略从句的主语与be动词。此题从句省略了he was.