Which example best represents a common property good?

A common property good is characterized by being non-excludable but rivalrous in consumption. This means that while individuals cannot be prevented from accessing the resource, one person's use of it can diminish the amount available for others.

The example of a popular public beach allowing open-access recreational fishing is a prime illustration of a common property good. Individuals can freely access the beach and engage in fishing without facing exclusion from using the beach. However, if too many people fish in one area, it may lead to overfishing, which reduces the availability of fish for others, highlighting the rivalrous nature of the good.

In contrast, the other choices represent different types of goods. A reserved seat in a theater and a ticket for an amusement park are examples of private goods, as they are both excludable and rivalrous—only the person with the ticket can use that seat or enjoy the amusement park rides. Similarly, a luxury hotel pool is also a private good since access is restricted to hotel guests, and its use is rivalrous; if one guest uses the pool, less space is available for others. Therefore, the example of the public beach effectively captures the essence of common property goods in its definition and characteristics.