What does marginal utility decrease as more units are consumed describe?

The concept of diminishing marginal utility refers to the decrease in the additional satisfaction or pleasure a consumer gains from consuming one more unit of a good or service as they continue to consume more of that good or service. Initially, when a person consumes the first few units of a product, each additional unit typically provides a significant boost in utility. However, as consumption increases, the added satisfaction from each subsequent unit tends to decline.

This principle is foundational in economics because it explains consumer behavior and demand. When consumers recognize that their additional satisfaction decreases with each unit, they may be less willing to pay as much for subsequent units, which can affect pricing and consumption choices in the market.

The other options, while related to economics, do not accurately describe the phenomenon of decreasing satisfaction with increased consumption. Opportunity cost deals with the cost of forgoing the next best alternative, total satisfaction refers to the overall pleasure derived from consuming goods, and consumer surplus quantifies the difference between what consumers are willing to pay versus what they actually pay. None of these capture the essence of diminishing marginal utility as precisely as the correct answer does.