The best definition of marginal benefit is: the additional income gained from selling an additional good. Marginal benefit refers to the maximum amount a consumer is willing to pay for one more unit of a good or service, or the additional satisfaction or value derived from consuming that extra unit. In business terms, this is often called marginal revenue, which is the increase in total revenue from selling one more unit of a product. It represents the incremental benefit received from producing or consuming an additional unit

. To clarify the other options:

• "The possible income from producing an additional item" is close but less precise than "additional income gained from selling an additional good," since marginal benefit focuses on the benefit or revenue from the sale, not just production.
• "The price of producing one additional unit of a good" defines marginal cost, not marginal benefit.
• "The financial gain from business activity minus expenses" defines profit, not marginal benefit.

Thus, the core concept of marginal benefit is the extra benefit or revenue from one more unit sold or consumed