Which of the following statements is not correct? a. some goods that are often thought of as public goods may be private goods in certain circumstances. for example, a lighthouse that protects a privately owned port may be a private good. b. antipoverty programs can be an example of a public good because everyone benefits from living in a society with less poverty. c. some goods that are often though of a private goods may be public goods in certain circumstances. for example, a candy bar could be a public good. d. the government must provide national defense because it is impossible to exclude people from its benefit, and the consumption of national defense is nonrival in consumption.