Answer: Charging one price at all times for all customers (D)
Step-by-step explanation:
Price discrimination is a pricing strategy where identical or similar goods or services are sold at different prices by the same producer to the customers. In price discrimination, companies charge customer different prices based on the willingness and ability of the customers to pay.
This can be seen on cinemas as people are charged different prices and airline companies. In the question above, charging a lower price for children, matinees and people over 65years are price discrimination. For price discrimination not to exist, everyone must pay the same price for enjoying similar good or service.