An airline's flight is about to take off. It has a few empty seats left aboard. If it lowers its prices, it can fill the remaining seats and fly at full capacity. What should be done?
a. Sell the additional standby seats at a discount since marginal costs of the additional passenger are almost zero and fly at full capacity
b. Sell the additional standby seats without a discount
c. Don't offer the additional seats for any price
d. None of the above