What is defined as the quantity of consumers willing and able to buy a product at a given price?

The correct answer is demand because it specifically refers to the quantity of consumers who are both willing and able to purchase a product at a specific price. Demand is a fundamental concept in economics that illustrates how consumer preferences influence market dynamics.

When the price of a product is set, demand varies depending on factors such as consumer income, preferences, and the price of related goods. A higher price typically leads to a lower quantity demanded, while a lower price generally encourages more purchases. This relationship is visually represented in a demand curve, which slopes downwards from left to right, reflecting the inverse relationship between price and quantity demanded.

In contrast, supply refers to the amount of a product that producers are willing and able to sell at a given price, while market value pertains to the price at which a product can be sold in the marketplace. Consumer interest might encompass broader considerations about what consumers are attracted to, but it doesn't specifically quantify the willingness and ability to purchase at a set price.