To treat a person justly is to treat that person with perfect impartiality. But our friends naturally expect us to attach more importance to their interests than to the interests of others. Hence, given that we try to maintain our friendships, we cannot succeed in being just to our friends. Which of the following must be assumed in order for the conclusion of the argument above to be properly drawn? ['People should not treat their friends less justly than they treat others.', "One cannot both treat someone impartially and value that person's interests above the interests of others.", 'The ideal of justice is irrelevant to most interpersonal relationships.', 'It is morally important to maintain close friendships.']