The police have ____ power to deal with such matters by ____ law.

A．the; the

B．不填；不填

C．不填；the

D．the；不填

质量为m的木块放在质量为M的木板上，如果木板与木块间，木板与地面间的动摩擦因数都是μ，那么，要把木板从木块下抽出，所加的水平力F的大小至少为______．