The correct answer is C) bipolar.
When the world has two superpowers, the world is bipolar.
An example of this term was the Cold War years when the Soviet Union and the United States embraced in an arms race and the world lived tense moments through all those years. The two superpowers wanted to be ahead of each other. The Soviet Union wanted to spread Communism in different countries of the world but the United States wanted to stop it. This created conflicts in North Korea and Vietnam, among many other incidents such as the Cuban Missile Crisis of October 1962.
