the premise already pointed that the US provides the best medical care, thus the medical care is better than that present anywhere in the world. BEST is the BEST, what's over it?
A logical objection to this could be 'a country that provides comparable care(to the one the US provides) and to all the people (rich or poor -- this has an edge over the US').
nothing, in the choices, seems a true objection to the remark. But, if I have to choose, I will go with the majority B