Which of the Following Best Describes the World's Superpowers Since

Which of the following best describes the world's superpowers since the end of World War II?

A) The United States has been the sole superpower since the end of World War II.
B) The United States and the Soviet Union were rival superpowers until the end of the Cold War,when the United States became the sole superpower.
C) The United States and the Soviet Union were rival superpowers until the Cuban Missile Crisis,when the United States and Russia became rival superpowers.
D) The United States and the Soviet Union were the only two rival superpowers until the end of the Cold War,when China also became a rival superpower.