单选题 I left for the office earlier than usual this morning ______ traffic jam.

A. at the risk of
B. in case of
C. for the sake of
D. in line with

【正确答案】 B

【答案解析】[解析] 考查常用短语的含义。 [解析] at the risk of冒……的风险；in case of万一，如果，防备；for the sake of为了……起见；in line with与……一致，符合。从句意可判断，“我”早走的原因是为了应付交通堵塞，而不足别的，因此in case of比较恰当。故答案为B。