Concept:Price elasticity measures how much the quantity demanded or quantity supplied changes when the price changes.Explanation:Price elasticity of demand shows the responsiveness of consumers to a change in price.Price elasticity of supply shows the responsiveness of sellers to a change in price.Both concepts focus on the reaction of quantity to a change in the market price of the product.Therefore, the correct option refers to consumers responding to a change in price.Answer:A. consumers are to a change in price