What Is One Important Difference Between International Politics and Domestic

What is one important difference between international politics and domestic politics?

A) In international politics there is no single government with the authority to resolve disputes among nations; within a country the government normally has such authority.
B) In international politics countries often have conflicting interests; within a country citizens have common interests.
C) In international politics countries stay in alliances for long periods; within a country citizens change political parties often.
D) In international politics countries never change borders; within a country the borders of states change often.