Which term is defined as the willingness and ability of buyers to purchase goods and services?

The correct term for the willingness and ability of buyers to purchase goods and services is indeed demand. Demand is a fundamental concept in economics that illustrates the relationship between the price of a good or service and the quantity that consumers are willing to purchase at various price levels. As price decreases, demand typically increases, reflecting consumers' willingness to buy more at lower prices, and vice versa.

Demand is influenced by various factors, including consumer preferences, income levels, the prices of related goods (substitutes and complements), and consumer expectations. Understanding demand is crucial for businesses when making decisions regarding production, pricing strategies, and market entry.

The other options are distinguished by their different meanings. Market Cap refers to the total market value of a company's outstanding shares of stock, which is not related to consumer purchasing behavior. Supply refers to the total amount of a particular good or service that producers are willing to sell at any given price, which is the counterpart to demand in market analysis. Utility represents the satisfaction or benefit derived from consuming a good or service, but it does not directly address the purchasing aspect of consumers.