Answer:
The correct answer is option c.
Explanation:
Equilibrium is achieved in any economic model at the point where the marginal cost is equal to marginal benefit.
The profit or net surplus for a rational decision-maker will be maximized when the marginal benefit is at least equal to the marginal cost. The higher the marginal benefit from the cost more will be the profit.
If the marginal benefit is lower than the marginal cost, it means the decision-maker is incurring a loss.