Why is it more difficult to roller blade across rough asphalt than it is to roller blade across smooth concrete?
A. Asphalt has more mass than concrete.
B. Friction on the roller blades is greater on asphalt than on concrete.
C. Roller blades exert a greater force on asphalt than they do on concrete.
D. The inertia of the roller blades is greater on asphalt then on concrete.