With this type of externality, in the absence of government intervention, the market equilibrium quantity produced will be socially optimal quantity.
Which of the following generate the type of externality previously described? Check all that apply.
1. The city where you live has granted a permit to put a movie theater in your neighborhood, causing traffic jams at night and on weekends.
2. A microbiology lab has published its breakthrough in swine flu research.
3. Kenji has planted several trees in his backyard that increase the beauty of the neighborhood, especially during the fall foliage season.
4. Your roommate Amy has bought a cat to which you are allergic.