Which good is non-excludable but rival in consumption?

• A. Public good
• B. Private good
• C. Common good
• D. Club good

Answer: (C)

Understanding how goods are classified by excludability and rivalry helps explain why some resources are shared and others are controlled. Non-excludable means you can’t easily prevent people from using the good, and rival means one person’s use reduces the amount available for others. A common good fits this mix: it’s available to everyone, but using it reduces its availability for others. Think of open-access fisheries or grazing land—no one can be easily blocked from using them, yet each fish caught or animal fed takes away from others’ potential yield. This setup often leads to overuse unless there are rules or property rights to manage it. This differs from a public good, which is non-excludable and non-rival (your use doesn’t diminish others’ ability to use it), a private good which is excludable and rival (owners can prevent use and each unit consumed reduces availability), and a club good which is excludable but non-rival up to a point (like a private park that can serve many without crowding until congestion sets in). So non-excludable but rival describes a common good.