They often praise the policeman _____ his courage.[ ]

A. in

B. on

C. for

D. at

旅客无正当理由拒绝铁路危险品检查而影响旅行时，责任由（）承担。

A.铁路公安

B.客运部门

C.旅客自己

D.铁路和旅客共同