Which term best describes a good that is non-excludable and non-rival in consumption?

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

Answer: (A)

Public goods are defined by two properties: non-excludability and non-rivalry. Non-excludable means it’s hard to prevent people from using the good, so you can’t easily charge everyone who benefits. Non-rival means one person’s use doesn’t reduce another’s ability to use it. When both hold, the good is best described as a public good. Markets tend to underprovide these because people can free-ride, letting others pay while they still benefit. That’s why such goods are often supplied by the government or through collective action. The other options don’t fit both properties: club goods are excludable, private goods are both excludable and rival, and common goods are non-excludable but rival.