Which statement about public goods is true?

• A. They are excludable and rival.
• B. They are excludable but non-rival.
• C. They are non-excludable and non-rival.
• D. They are non-excludable but rival.

Answer: (C)

Public goods have two defining features: non-excludability and non-rivalry. Non-excludable means it's difficult or costly to prevent people from using the good, and non-rival means one person’s use does not reduce another's ability to use it. Because people can benefit without paying, the free-rider problem arises, and private markets typically undersupply such goods, often requiring government provision or funding. The other descriptions mix in excludability or rivalry, which would describe private or club/common resources rather than public goods. Therefore, the statement that is true is that public goods are non-excludable and non-rival.