At the Utility Maximizing Equilibrium for Two Goods, X and Y

Multiple Choice

At the utility maximizing equilibrium for two goods, X and Y, which of the following must be true?

A) The marginal utility per dollar spent on X will exceed the marginal utility per dollar spent on Y.
B) The total expenditure will be the same for each good.
C) The marginal utility per dollar from X equals the marginal utility per dollar from Y.
D) The marginal utility will be the same for each good.