A car moves at constant speed around a flat (unbanked) circular track. Which of the following best describes the horizontal force that keeps the car following its circular path?
a) The forward thrust from the engine acts toward the center, providing the required force.
b) A horizontal component of the normal force from the road acts toward the center, providing the required force.
c) Static friction between the tires and the road acts toward the center, providing the required force.
d) Kinetic friction between the tires and the road acts toward the center, providing the required force.