This is the best way I have thought of the problem.A. to be solvedB. solvingC. to solveD.

问题补充：

This is the best way I have thought of the problem.

A. to be solved

B. solving

C. to solve

D. solves

答案：

A. to be solved

B. solving

(答案→)C. to solve

D. solves

解析：考查不定式做定语，分析句子成分，I have thought of是定语从句修饰the best way，后面的不定式也是定语修饰the best way，句意：这是我能想到的最好的解决问题的办法。选C。