Answer: Option(B) is correct.
Explanation:
Correct Option: Diminishing marginal utility.
Diminishing marginal utility states that as the consumer consumes more and more units of a commodity the utility derived from an additional unit goes on diminishing.
For example; if a consumer consumes an ice-cream. The first scoop gives him 100% satisfaction, second scoop gives him 70%, third scoop gives him 40% and so on...
So, utility derived from an additional unit goes on diminishing.