World government is an old idea in political theory that one authority can and should sustain order at the global level. Pax Romana and Pax Britannica, for example, are known as eras of relative peace and order in world history that was provided by a single power- the hegemon. We see the reemergence of this idea especially after the Second World War in the theory of world government. In post-WWII world, the United States of America is considered to be the world government with military bases all around the world. Therefore, the correct option is A.