The correct answer is: B. Prof. A. Marshall.
The law of diminishing marginal utility is a fundamental concept in economics that states that as a consumer acquires more of a good, the additional satisfaction (or utility) that they receive from each additional unit of the good decreases.
The law of diminishing marginal utility was first proposed by Alfred Marshall in his 1890 book, Principles of Economics. Marshall argued that the law of diminishing marginal utility was a fundamental principle of human nature, and that it could be used to explain a wide range of economic phenomena.
The law of diminishing marginal utility has a number of important implications for economic theory. For example, it can be used to explain why consumers are willing to pay more for the first unit of a good than they are for subsequent units. It can also be used to explain why firms produce a variety of goods, rather than just one good.
The law of diminishing marginal utility is a powerful tool for understanding economic behavior. It is a fundamental concept that is used in a wide range of economic models.
The other options are incorrect.
- Option A is incorrect because Paul Samuelson was a Nobel Prize-winning economist who lived from 1915 to 2009. He is best known for his work on general equilibrium theory and welfare economics. However, he did not propose the law of diminishing marginal utility.
- Option C is incorrect because John Hicks was a Nobel Prize-winning economist who lived from 1904 to 1989. He is best known for his work on welfare economics and the theory of value. However, he did not propose the law of diminishing marginal utility.
- Option D is incorrect because Mrs. John Robinson was a fictional character in the novel “The Economics of Imperfect Competition” by Joan Robinson. She is not a real person, and she did not propose the law of diminishing marginal utility.