单项选择题是数学试题的重要组成部分，当你遇到不懂做的情况时，如果你随便选一个答案（假设每个题目有4个备选答案），那么你答对的可能性为（    ）．

I told them not everybody could run as fast as you did, ______?

A．could he

B．didn't I

C．didn't you

D．couldn’t they