Final answer:
John Rawls' Difference Principle states that injustice is only permitted if it benefits the least advantaged, aiming for societal harmony by improving their status within the social structure. Therefore, within the context of the provided options, the correct answer to the question 'Rawls believes that injustice is only allowed if its existence benefits the least advantaged' would be option A.
Step-by-step explanation:
The question at hand revolves around John Rawls' understanding of justice, focusing on the conditions under which inequality could be considered justifiable in a society. Rawls developed the Difference Principle, which stipulates that inequalities in a society are permissible only under the condition that they are to the greatest benefit of the least advantaged. This is indicative of the deeper philosophy that Rawls held, where human freedom and social welfare are both seen as crucial to the structure of a society.
Therefore, within the context of the provided options, the correct answer to the question 'Rawls believes that injustice is only allowed if its existence benefits the least advantaged' would be option A, meaning it promotes societal harmony in a way that maximizes the position of the least advantaged members of society, consistent with the just savings principle and conditions of fair equality of opportunity.