What important federalist idea is expressed in this excerpt

It's C, because feds are for the, powerful big federal union centralized "american" national government.

This contradicts D, so it can not be D, since feds were NOT the kind of people to say. "Hey stop !!! The American government is bullying my Virginia." No virigina does not have soveringy in the eyes of feds. The USA is the powerful nation holding the states - The alliance of states is stronger than the individual power of states.

It's important to recognize that some colonists and early Americans did not see them selves as together as one. " We are not Americans as a nation, but only a region." Like Europe with all their different states and nations. 
It also says all past " But if the union" Obvious for what I think.

You don’t have to names or other options up here so idk dude