Which of the following best defines consumer surplus?

Consumer surplus is defined as the difference between the highest price a consumer is willing to pay for a good or service and the actual price they end up paying. This concept reflects the benefit that consumers receive when they purchase a product for less than what they were prepared to pay. It measures the additional satisfaction or utility consumers receive from a transaction because they pay a lower price.

For example, if a consumer is willing to pay $50 for a shirt but buys it for $30, the consumer surplus is $20. This concept is important in understanding consumer behavior and the efficiency of markets, as it indicates the extra benefit consumers receive from market transactions. The other options present different economic concepts that do not relate directly to the idea of surplus associated with consumer transactions.