Correct Answer :
C. The Law of Diminishing Marginal Utility
Gossen's laws, named for Hermann Heinrich Gossen (1810 - 1858), are three ostensible laws of economics: Gossen's First Law is the law of diminishing marginal utility: that marginal utilities are diminishing across the ranges relevant to decision-making. Gossen's Second Law, which presumes that utility is at least weakly quantified, is that in equilibrium an agent will allocate expenditures so that the ratio of marginal utility to price (marginal cost of acquisition) is equal across all goods and services.