To make a rational choice, a person a. compares the extra benefits of one more unit to the extra costs of one more unit. b. adds the total costs to determine if the total is small enough. c. adds the total benefits and the total costs and then compares the two totals. d. adds the total benefits to determine if the total is large enough. e. takes account of all benefits and all opportunity costs, including both marginal costs and sunk costs.

A. compares the extra benefits of one more unit to the extra costs of one more unit.

Explanation:

                             Rational choice is a theory. It is better known as rational action theory or the choice theory. It may defined as when individuals make logical calculations and arguments to make some sensible and rational choices to achieve the results which are aligned with the individuals personal objectives.

                              So in order to make a rational choice, an individual usually compares the two units and examines the extra benefits of one unit to the extra cost of the one unit compared to the other.

Thus the answer is

A. compares the extra benefits of one more unit to the extra costs of one more unit.

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