液化氯化石蜡的含氯量在（）左右，可作橡胶、纤维蜡、乙烯类树脂的增韧剂。

A、10%

B、20%

C、40%

D、60%

People were afraid to leave their house, （） the police had been ordered to stand by in case of emergency, they were just as confused and helpless as anybody else.

A. and even if

B. but since

C. however after

D. for though