Suppose an individual knows that the marginal utility he receives from the next apple is 5 and that the price of an apple is $2. He also knows that the marginal utility he receives from the next orange is 3 and the price of an orange is $1. If the individual is choosing optimally, the next good he will buy is a. an apple because the marginal utility of the apple is greater. b. an orange because the marginal utility per dollar spent on an orange is greater. c. an orange because the marginal utility of the orange is greater. d. an apple because the marginal utility per dollar spent on an apple is greater