Concept:Inertia is the tendency of a body to resist any change in its state of rest or uniform motion.Explanation:A body at rest stays at rest unless acted on by an external force.A body in motion continues moving in a straight line at constant speed unless a force acts on it.This resistance to change in motion is called inertia.It depends on the mass of the body.Therefore, the correct option is inertia.Answer:D. Inertia