35. A small box of mass m is placed on top of a larger box of mass 2m as shown in the diagram at right. When a force F is applied to the large box, both boxes accelerate to the right with the same acceleration. If the coefficient of friction between all surfaces is μ, what would be the force accelerating the smaller mass?
(A) 3F−mgμ
(B) F−3mgμ
(C) F−mgμ
(D) 3F−mgμ