Question

economists use the word marginal to mean an extra or additional benefit or cost of a decision. an optimal decision occurs when
a. marginal benefit is greater than marginal cost.
b. marginal benefit is maximized.
c. marginal cost is zero.
d. marginal benefit equals marginal cost.

Explanation:

In economics, an optimal decision is made when the additional benefit (marginal benefit) from a decision equals the additional cost (marginal cost). If marginal benefit is greater than marginal cost, more of an activity should be done. If marginal cost is greater than marginal benefit, less of an activity should be done.

Answer:

D. marginal benefit equals marginal cost.