what is the answer to this question? Can you explain in detail?

5. An individual's preferences are represented by the utility function U(X, Y) =(X1/2 + yl/2)? Which of the following statements is false? d a. The marginal utility of y decreases as y increases, holding x constant. b. Preferences are monotonic in both goods. c. The marginal rate of substitution of x for y increases as y increases, holding x constant. d. The consumer is willing to give up an increasing amount of good y for each additional unit of good x, to remain as well off