What is defined as consumers' willingness and ability to consume a given good?

The concept of demand encompasses consumers' willingness and ability to purchase a certain good or service at various price levels. It reflects preferences, income levels, and the prices of related goods, which all contribute to how much of a product consumers are prepared to buy. Demand is typically represented by a demand curve, which illustrates this relationship between price and quantity demanded over a range of prices.

In contrast, supply refers to how much of a good producers are willing to sell at different prices, equilibrium price is where supply and demand meet, and marginal benefit refers to the additional satisfaction gained from consuming an additional unit of a good or service. Therefore, the definition of demand accurately captures the willingness and ability to consume a product, making it the correct choice.