It never occurred to me you could succeed in persuading him to change his mind．
A. which
B. what
C. that
D. if
网友回答
A. which
B. what
(答案→)C. that
D. if
解析：考查主语从句。It是形式主语，真正的主语是 you could succeed in persuading him to change his mind这一主语从句，且从句不缺成分，句意完整，所以用that引导。选C。