The correct answer is A. enjoys something without paying for it.

The free-rider problem is an economic term used for situations in which a person obtains benefits from something without contributing anything to obtain those benefits. In other words, a person gains without any cost. The free-rider problem is a market failure that is very often encountered in public goods. A public good is available for everyone, however, not everyone pays taxes that provided the government with funds to create that public good. The free-rider concept is not associated with irrationality or utility maximization.