To Make a Rational Choice, a Person

To make a rational choice, a person

A) adds the total benefits to determine if the total is large enough.
B) adds the total costs to determine if the total is small enough.
C) compares the extra benefits of one more unit to the extra costs of one more unit.
D) adds the total benefits and the total costs and then compares the two totals.
E) takes account of all benefits and all opportunity costs, including both marginal costs and sunk costs.