Identify the following situations as an example of a negative or a positive externality:

a. You are a birder (bird watcher), and your neighbor has put up several birdhouses in the yard as well as planting trees and flowers that attract birds.

b. Your neighbor paints his house a hideous color.

c. Investments in private education raise your country’s standard of living.

d. Trash dumped upstream flows downstream right past your home.

e. Your roommate is a smoker, but you are a nonsmoker.