The law of diminishing marginal utility indicates that the slope of the marginal utility curve is generally:

A) negative.
B) vertical.
C) horizontal.
D) positive.

The law of diminishing marginal utility states that as a consumer consumes more units of a good or service, the additional satisfaction or utility derived from each additional unit consumed will eventually decrease. This implies that the slope of the marginal utility curve will be negative, as the marginal utility of each additional unit consumed is decreasing.