Case study: Suppose your father comes back home from work and you offer him a glass of juice. The first glass of juice will give him great satisfaction. The satisfaction from second glass of juice will be relatively less. With further consumption, a stage will come when he would not require any more glass of water. If he is forced to consume even one glass that would lead to disutility.

What happens to the marginal utility if consumption is continued beyond the "Saturation point"?

Marginal utility becomes negative

The correct answer is Option 2: Marginal utility becomes negative

The "Saturation point" is the point where total utility derived from the consumption of the commodity is maximum. At this point, the marginal utility stands to be zero. Any consumption beyond this would result in disutility and the marginal utility becomes negative causing the total utility to decline.