What best exemplifies a common property resource?

A common property resource is a type of good that is non-excludable but rivalrous, meaning that multiple individuals can access it, but one person's use of the resource can diminish another's ability to use it. An aquifer used by farmers and ranchers fits this definition perfectly because it is a water source that is generally accessible to those with the means to access it but can be depleted or polluted through overuse.

Farmers and ranchers drawing water from the aquifer can create competition for this resource, leading to potential over-extraction and sustainability issues. This situation illustrates the classic problem of common resources, where individual interests may lead to the depletion of a resource that is available to everyone.

In contrast, a public beach is more of a shared space but often involves regulations that manage use, while a private lake is excludable, making it not a common property resource. A community garden, while shared and collaborative, typically operates under specific agreements and guidelines that mitigate the overuse concern found in common property resources.

Thus, the aquifer stands out as the quintessential example of a common property resource, capturing the essence of how shared access can lead to potential rivalry and sustainability challenges.