Which of the following statements about marginal utility is true?

The statement that marginal utility decreases as more of a good is consumed is true due to the law of diminishing marginal utility. This economic principle states that as a person consumes additional units of a good or service, the satisfaction or utility gained from each subsequent unit will eventually decline. For example, think about eating slices of pizza; the first slice may provide a high level of satisfaction, but as you continue eating more slices, the additional satisfaction from each subsequent slice diminishes. This decrease in marginal utility is a crucial concept in understanding consumer choice and demand, as consumers will allocate their spending based on the level of satisfaction they expect to receive from additional consumption.

The other statements related to marginal utility are not accurate. While marginal utility can be positive, it can also become zero or even negative when a consumer derives no satisfaction, or experiences dissatisfaction, from consuming more of a good. Hence, marginal utility is not always positive. Additionally, since marginal utility can indeed be negative, the idea that it can never be negative is incorrect. Finally, marginal utility is highly relevant to demand, as changes in marginal utility directly influence consumer purchasing decisions and the demand curve.