— Why do you drink so much tea? 

— Well, _____ it doesn't keep me awake in the nights.[ ]

A. although

B. as soon as

C. as long as

D. while

采取强制的、暴力的手段制服正在实施暴力犯罪的犯罪分子；对付犯罪分子的暴力反抗、拒捕、报复、袭击等；在处理治安案件或事件中受到不法分子的殴打伤害等，这体现了公安工作的( )。

A．危险性

B．复杂性

C．隐蔽性

D．艰苦性