---Why do you think he can succeed?---He believes in himself is the most important I th

问题补充：

---Why do you think he can succeed?

---He believes in himself, is the most important, I think.

A. which?

B. what

C. that

D. who

答案：

(答案→)A. which?

B. what

C. that

D. who

解析：此题考查的是非限制性定语从句，that 不能引导非限制性定语从句，what 不能引导定语从句，who 作主语指代前面的先行词“人”，which引导非限制性定语从句指前面的先行词也可指前半句话的含义，此处选which指的是前半句话的含义。