Which one of the following statements about the states within the United States is false?

Group of answer choices

The Constitution had certain provisions to promote free trade between the states.


If a state has the consent of Congress and imposes a duty on imports and exports the net proceeds of such duty will be for its own use.


Not every city in the United States is contained within a state.


A state may engage in war without the consent of Congress but only in very dire circumstances.


A state may not keep troops in times of peace without consent of Congress.