The price elasticity of demand is defined as:

The price elasticity of demand provides a measure of how responsive the quantity demanded of a good is to a change in its price. Specifically, it quantifies the relationship between a change in price and the resulting change in quantity demanded by expressing this relationship as a percentage.

The correct definition states that price elasticity of demand is the percentage change in quantity demanded divided by the percentage change in price. This formula captures the sensitivity of consumers’ purchasing decisions relative to price changes. A higher elasticity indicates that consumers are more responsive to price changes, while a lower elasticity suggests that quantity demanded is less sensitive to price fluctuations.

In contrast, the other options do not accurately reflect the concept of price elasticity of demand. The first option discusses the ratio of price change to quantity change, which does not incorporate the percentage aspect necessary for elasticity. The second option refers to total revenue and quantity demanded, which is related to revenue calculations but not directly to how quantity demanded responds to price changes. The last option addresses consumer income and its effect on demand, which pertains to income elasticity rather than price elasticity. Thus, the defining feature of price elasticity being the ratio of percentage changes is what makes the correct answer accurate.