julie has preferences for food, f, and clothing, c described by a utility function u(f,c)+f*c. her marginal utilities are Muf=c and Muc=f. suppose that food cost $1 a unit and that clothing costs $2 a unit. julie has $12 to spend on food and clothing. sketch julie indifference curves corresponding to utility levels U=12, u=18 and u=24. using the graph find the optimal/utility-maximizing choice of food and clothing. please put food on x-axis and clothing on y-axis.