In Figure 5.1, at 4 units consumed marginal utility is: Figure 5.1 Two graphs vertically stacked-Upper graph is a hill shaped TU curve; lower graph is a downward sloping MU curve; the maximum of the total utility curve in the upper graph occurs where MU is zero at quantity 4 in the lower graph In Figure 5.1, at 4 units consumed marginal utility is: 4 0 -4 cannot be determined