When I read that problem, I immediately discarded answers A and B because they are just wrong. Strength and such would have absolutely no affect on violating Ne

When I read that problem, I immediately discarded answers A and B because they are just wrong. Strength and such would have absolutely no affect on violating Newton's third law. It seems like you are waffling in your intuition of the problem which suggests that this problem has revealed an actual problem in your understanding of the fundamentals (which means it is a well designed problem). There is no stretching of the model or anything happening. Even if you account for higher order effects, A and B would still not be true.