I could have been on time for the meeting,but I ---- in a tr

I could have been on time for the meeting,but I ____ in a traffic jam for over half an hour.
A.have caught B.have been caught C.was caught D.caught这题的正确答案是C.这里为什么要用过去式不是用完成时?"for+一段时间"不是完成时的标志吗?