4. [25 points] A consumer's preferences over food (x) and other goods (y) are given by U(x,y) = xy with marginal utilities MU, = y and MUy = x. The consumer's income is $32,400. a. Calculate the optimal basket when Px=40 and Py= 10. b. Calculate the income and substitution effects (in terms of changes in quantity of x demanded) of an increase in the price of food to Px=90. c. Calculate the Compensating Variation of the price change