United Airlines flies a plane from LA to NY at 8 o'clock on Tuesday morning only 25 percent full. On Friday, the same flight is overbooked by 15 percent. United is unable to capture and save the unused seats from the previous flight, and instead has to pay passengers to fly on future flights. This is an example of the ________ of services.
1) efficiency
2) inefficiency
3) overbooking
4) cost-effectiveness