Smoking hurts not only the smoke

Smoking hurts not only the smokers, but also the people around them ( )second-hand smoke.
A、because
B、because of
C、as
D、as of
【正确答案】：B
【题目解析】：because of接短语，because和as接句子，as for 关于 句子含义是吸烟不仅对吸烟者有害，而且因为二手烟对周边的人也一样。