--I wonder why Mr. Brown hasn t showed up at the meeting yet. --I m not sure but he____

--I wonder why Mr. Brown hasn" t showed up at the meeting yet. --I" m not sure, but he__________ in a traffic jam driving here.

A. could be stuck

B. ,might stuck

C. might have been stuck

D. must have stuck

请帮忙给出正确答案和分析，谢谢！