Thanks for the question! So we’re looking for something that most strengthens the argument. Specifically, something that strengthens the idea that general principles of justice are never sufficient to determine details of social policies fixed within a certain state.
(A) talks about electoral principles, which can’t automatically be equated with principles of justice.
(B) is about economic principles, which again, can’t automatically be equated with principles of justice.
(C) gets it backwards. It’s different principles, but the same policy. We want the same general principles, but different policies.
(D) is the correct answer and fits what we want.
(E) gets it backwards as well. Again, different principles, but the same policy (unemployment benefits).
Hope this helps! Feel free to ask any other questions that you might have.