Which of the following are actual Pareto-efficient changes? Explain briefly.

a. You buy an air conditioner as it is hotter this summer due to climate change.

b. You go salmon-fishing but you throw your catch back into the river.

c. You use your father’s car instead of buying your own to save money. You only use it when your father does not.

d. Your economics professor decides to skip a class and offers no make-up opportunities.