A rational decision maker takes an action if and only if

A rational decision maker takes action if and only if the marginal benefit of the action exceeds the marginal cost.

Explanation:

Rational people always think at the margin. Decision makers generally consider both the explicit and implicit costs of their actions.

The decision-making is the process of making choices in the optimal level of benefit or utility for an individual. Rational decision making is a multi-step process that makes choices between the alternatives.

A rational decision maker takes action if and only if the marginal benefit of the action exceeds the marginal cost.