Concept:Matter is made of particles that are always in motion, even in liquids.Explanation:The kinetic theory of matter states that molecules are never completely stationary.In a liquid, molecules vibrate and move past one another, so they are not at rest.Brownian motion provides visible evidence that tiny particles are constantly moving due to molecular collisions.Therefore, saying that liquid molecules are stationary is incorrect.Answer:A. Molecules of a liquid are stationary