Which of the following best summarizes Rawls' definition of Justice as Fairness?

a. The principles that free and rational persons would adopt in accordance with the Categorical Imperative
b. The principles that free and rational persons would adopt because they think that they bring about the most happiness and least suffering for everyone
c. The principles that free and rational persons would adopt in order to make sure that everything is exactly equal between all members of society
d. The principles that free and rational persons concerned to further their own interests would accept in an initial position of equality