A Block of Mass M Is Sliding Down a Rough $\theta$

Multiple Choice

A block of mass M is sliding down a rough inclined surface that makes an angle $\theta$ with respect to the horizontal.If the coefficient of static friction is $\mu$ _s and kinetic friction $\mu$ _k,then the acceleration of the block down the incline is equal to:

A) gsin $\theta$ - g $\mu$ _s $\times$ cos $\theta$
B) gcos $\theta$ - g $\mu$ _k $\times$ cos $\theta$
C) g $\mu$ _s $\times$ cos $\theta$ - gsin $\theta$
D) gsin $\theta$ - g $\mu$ _k $\times$ cos $\theta$
E) gsin $\theta$ - g $\mu$ _s $\times$ cos $\theta$ - g $\mu$ _k $\times$ cos $\theta$