You may have your own decision on this matter and I have little doubt you’ll succeed.A. i

问题补充：

You may have your own decision on this matter,and I have little doubt you’ll succeed.

A. if

B. whether

C. that

D. what 

答案：

A. if

B. whether

(答案→)C. that

D. what 

解析：have some(little) doubt that...中that引导从句为同位语从句。