What does the concept of elasticity in economics measure?

Elasticity in economics is a critical concept that measures the responsiveness of one variable to changes in another variable. This often pertains to how the quantity demanded of a good or service reacts to changes in price or how changes in income affect demand.

For instance, if the price of a product increases and as a result, the quantity demanded decreases significantly, this indicates high price elasticity of demand. Conversely, if the quantity demanded changes very little in response to price changes, the demand is said to be inelastic. Elasticity thus quantifies how sensitive the demand or supply of a good is relative to changes in price, income, or other factors, providing valuable insights for consumers and producers in economic decision-making.

The other options focus on unrelated concepts. The first option describes a scenario of demand shifting without price changes, which does not capture the essence of elasticity. The third option refers to price stability, a different economic phenomenon that doesn't consider responsiveness. Finally, the fourth option concerns quantity supplied rather than the changes in response to another variable, which is not the focus of elasticity.