I understand why C is correct but it seems like it may require you to read something into the stimulus. The argument presented is simply that there must be widespread agreement about the reliability of the DNA tests in order for them to be admissible in court. That doesn't require the controversy to be as varied as the explanation for this answer choice suggests. Even if the difference in how the scientists assess reliability is only 98% vs. 99%, the argument is just saying that there cannot be widespread disagreement however large or small. Can someone clear this up for me?

I'm confused why this assumption is necessary rather than sufficient. Yes, if D is true the argument holds. But couldn't the argument hold without B? For example, maybe any law presented in polemical terms cannot benefit constituents at face value. Why does the argument depend on repugnance and enthusiasm relating directly to the necessary condition mentioned in the first sentence?