The reason he was late again was that he was caught in a traffic jam. A. whichB. in whic

问题补充：

The reason he was late again was that he was caught in a traffic jam.

A. which

B. in which

C. for which

D. of which

答案：

A. which

B. in which

(答案→)C. for which

D. of which

解析：句意：他再次迟到的原因是他被困在了交通堵塞中。通过分析句子结构，可知这个句子中包含一个定语从句，表示原因，用介词for，选C。