What did he say his stupid behavior?-- He admitted having made a serious mistake. A.

问题补充：

-- What did he say his stupid behavior?

-- He admitted having made a serious mistake.

A. in front of

B. in explanation of

C. in case of

D. in fear of

答案：

A. in front of

(答案→)B. in explanation of

C. in case of

D. in fear of

解析：A. in front of：在……前面； B. in explanation of ：对……作出解释；C. in case of：遇到……的时候；D. in fear of：担心……、害怕……。题意：他对自己的行为作何解释？故B项正确。