Final answer:
If marginal cost exceeds marginal benefit, rational decision-makers will generally choose to decrease production or avoid the action, as the costs outweigh the potential gains.
Step-by-step explanation:
When marginal cost is greater than marginal benefit, the decision-maker may choose to decrease production or not take the action under consideration. This is because the costs associated with the decision are higher than the gains, indicating that resources could be allocated more efficiently elsewhere. It is a fundamental principle in economics that for optimal decision-making, an action should only be taken if the marginal benefits equal or exceed the marginal costs. If the price someone is willing to pay (market price P) is lower than the marginal cost (MC), it signals that society values the good or service less than it costs to produce an additional unit, and thus less should be produced.