Which of the following is an example of marginal benefit?

Marginal benefit refers to the additional satisfaction or utility gained from consuming one more unit of a good or service. In this context, option B accurately represents marginal benefit because it specifically addresses the utility derived from the consumption of an additional unit. This concept is fundamental in economics, as it helps individuals and businesses make informed decisions about consumption and production by weighing the additional benefits against the additional costs.

The other choices, while related to economic concepts, do not encapsulate marginal benefit. For instance, total profit from selling goods measures overall financial performance rather than the incremental gain from one additional unit. Fixed costs pertain to expenses that do not change with the level of output and do not reflect the benefits of consuming extra units. Average income in an industry provides information about overall earnings but does not convey the specific incremental value derived from consuming an additional unit of a product. Thus, option B is the clear example of marginal benefit in this question.