Which of the following is considered a public good?

Public goods are defined by two key characteristics: they are non-excludable, meaning that individuals cannot be effectively excluded from using them, and they are non-rivalrous, meaning that one person's use of the good does not diminish the availability of the good for others.

Public libraries exemplify this concept, as they provide access to resources and information without excluding individuals based on their ability to pay. Anyone can use the library services regardless of whether they have contributed to funding them, which reflects the non-excludable nature of public goods. Similarly, street lighting benefits everyone in the vicinity, enhancing safety and visibility for all without diminishing the light available to any single individual.

In contrast, private clubs and subscription services are exclusive and require payment or membership for access, making them excludable. Government offices typically serve as administrative spaces rather than goods accessible to the public in the same sense, while private healthcare is inherently excludable, as individuals must pay to receive services. Luxury tax incentives and real estate pertain more to economic policies and transactions that do not fit the definition of public goods. Thus, public libraries and street lighting are the most fitting examples of public goods among the options provided.