Analogy questions are often annoying, but we should always start with the passage. In the passage, we take an idea from a different discipline, economics, and apply that to our discipline to show that two things we thought were in conflict are actually approaching the same idea.
In b, we take an idea from one discipline and apply it to our discipline, and use it to show that two things we though we're going in different directions are actually going in the same direction.
I don't love the idea of diverging and parallel lines, but it is closer to the idea of showing things are not actually in conflict than any of the other answer choices.