We all think it most foolish this mistake.
A. for you making
B. of you to make
C. you to make
D. for you to make
网友回答
A. for you making
(答案→)B. of you to make
C. you to make
D. for you to make
解析：考查固定句型。It is+形容词+of sb. to do sth.其中的形容词修饰人。句意“我们都认为你犯这个错误是很愚蠢的。”故选B。