Which of the Following Best Explains Why It Is Sometimes

Which of the following best explains why it is sometimes efficient to charge a positive price for the use of some products such as museums, beaches, and roads?

A) Once these products become congested they become rivalrous, marginal cost is positive, and a positive price is then efficient.
B) Each person consuming the product has a positive marginal benefit and should therefore pay a positive price.
C) Since these products are non- excludable, it is sometimes efficient to charge a positive price.
D) Since these products are excludable, marginal cost is positive, and a positive price is appropriate.
E) Since these products are excludable and non- rivalrous, it is always efficient to charge a positive price.