Answer:
c. percentage change in price and percentage change in quantity demanded.
Explanation:
A price elasticity of demand can be defined as a measure of the responsiveness of the quantity of a product demanded with respect to a change in price of the product, all things being equal.
The price-elasticity of demand coefficient, Ed, is measured in terms of percentage change in price and percentage change in quantity demanded.
The demand for goods is said to be elastic, when the quantity of goods demanded by consumers with respect to change in price is very large. Thus, the more easily a consumer can switch to a substitute product in relation to change in price, the greater the elasticity of demand.
Generally, consumers would like to be buy a product as its price falls or become inexpensive.
For substitute products (goods), the price elasticity of demand is always positive because the demand of a product increases when the price of its close substitute (alternative) increases.
If the price elasticity of demand for a product equals 1, as its price rises the total revenue does not change because the demand is unit elastic.