How is demand defined in economic terms?

Demand in economic terms refers to consumer willingness to purchase a product at various price levels. It captures not only the desire for a good or service but also the ability to pay for it, reflecting consumers' preferences and their purchasing power. The concept of demand is pivotal in understanding market dynamics, as it directly influences how much of a product will be sold at different prices, leading to the establishment of the market equilibrium between supply and demand.

While the other options relate to economic concepts, they do not accurately define demand. The amount of a product available for sale refers to supply, the number of suppliers in the market pertains to market competition and supply dynamics, and the prices set by producers are aspects of market pricing rather than consumer behavior. Thus, defining demand through consumer willingness to purchase highlights its fundamental role in shaping market trends and economies.