—What led to his success ?—He succeed working hard .A. toB. inC. throughD. by

问题补充：

—What led to his success ?

—He succeed working hard .

A. to

B. in

C. through

D. by

答案：

A. to

B. in

C. through

(答案→)D. by

解析：本题回答语的含义是他通过努力工作而获得成功，by表示做某事的方式，与本题的题意相符，故本题选D。