The limits on The powers of the states as explained in Article VI?

Which sentence BEST summarizes the limits on the powers of the states as explained in Article VI? A) States cannot create foreign alliances or conflicts without the approval of Congress.

B) States and their representatives cannot accept gifts or payments from foreign leaders.

C) States cannot keep up armed forces or forts except for the purpose of a militia.

D) States may engage in wars without approval of Congress only if they are directly attacked.