One of the Reasons Consumers Can Purchase Cheap Flights or Hotel

One of the reasons consumers can purchase cheap flights or hotel rooms on Web sites such as Expedia.com and Hotels.com is due to the fact that airlines cannot sell the seat on a specific flight after the plane takes off or hotels cannot recoup the revenue from that room for that night once the night passes. Which unique characteristic of services does this illustrate?

A) intangibility
B) inseparability
C) perishability
D) simultaneous production and consumption
E) variability