Answer:
a. not possible to find a transaction that will make at least one person better off without harming others.
Explanation:
A Pareto improvement refers to a situation in which a change in allocation of resources helps at least one person without damaging anyone. On the other hand, a Pareto efficient situation is one in which no more Pareto improvements can be made (or where it is not possible to find a transaction that will make at least one person better off without harming others).
