Final answer:
A shirt at a clothing store is not a public good because it is excludable, while national defense, flood control projects, and environmental protection are examples of public goods that are available to everyone.
Step-by-step explanation:
Public goods are goods or services that are available to all without charge. They are nonexcludable, meaning that it is difficult to exclude people from using or benefiting from them. In this case, a shirt at a clothing store is not a public good because it is excludable – only the person who purchases the shirt can use or benefit from it. On the other hand, national defense, flood control projects, and environmental protection are all examples of public goods because they are nonexcludable and available to everyone.
Shirts at a clothing store are not a public good because they are excludable; people must pay to obtain them, unlike national defense, flood control projects, and environmental protection, which are nonexcludable and benefit all members of society.
The item that is NOT a public good among the choices given is shirts at a clothing store. Public goods are characterized by being nonexcludable and nonrival. Nonexcludable means that no one can be prevented from accessing them once they are provided. In contrast, shirts at a clothing store are excludable because individuals can be prevented from obtaining them, typically through the requirement of payment. National defense, flood control projects, and environmental protection are all examples of public goods because they benefit all members of society and individuals cannot be excluded from their benefits.