2 . Balancing utility and price Suppose Musashi has to choose between purchasing plane tickets and water. Which of the following is the utility-maximizing rule that Musashi should follow while choosing the optimal quantities of these two goods? (Note: In the answer options that follow, MU stands for "marginal utility,") O (MU of Water) x ( Price of Water) = (MU of Plane Tickets) x (Price of Plane Tickets) MU of Water MU of Plane Tickets O Price of Plane Tickets Price of Water O MU of Water = MU of Plane Tickets MU of Water MU of Plane Tickets O Price of Water Price of Plane Tickets greater less Since water costs little and plane tickets are expensive, it must follow that when p se their optimal quantities of water and plane tickets to purchase, the marginal utility they receive from the last gallon of water they buy is than the marginal utility they receive from the last plane ticket they buy