Which one of the following statements concerning static friction is FALSE?
Select one:
a. The static friction force always opposes the force trying to cause motion.
b. The static friction force depends on the surface area of the object in contact with the surface.
c. The magnitude of the static friction force is proportional to the normal force between the object and the surface.
d. Static friction varies from zero up to a maximum value, depending on the force which is trying to move the object.
e. The magnitude of the maximum static friction force is proportional to the coefficient of static friction between the object and surface, μs.