The Law of Diminishing Marginal Utility states that when more and more units of a commodity are consumed, Marginal Utility _____.

begins to decrease.

The correct answer is Option (3) → begins to decrease.

Law of Diminishing Marginal Utility states that marginal utility from consuming each additional unit of a commodity declines as its consumption increases, while keeping consumption of other commodities constant.

For example, the first slice of pizza might give you great satisfaction, the second slightly less, and by the fourth or fifth, your satisfaction from each extra slice starts to decrease.