Block A of mass m rests on top of block B of mass 2m. The coefficient of static friction between the blocks is large enough that they do not slip relative to each other. The coefficient of kinetic friction between block B and the floor is much smaller. A horizontal force F is applied to the right on block A, causing both blocks to accelerate while block B slides across the floor.
Which option correctly describes the type and direction of each frictional force acting on block B?
a) Top surface: kinetic friction directed to the right; bottom surface: static friction directed to the left
b) Top surface: static friction directed to the right; bottom surface: kinetic friction directed to the left
c) Top surface: static friction directed to the left; bottom surface: kinetic friction directed to the right
d) Top surface: static friction directed to the right; bottom surface: static friction directed to the left