What best describes the governments of the United States and the Soviet Union after World War II?
 A. The United States had a single-party system, and the Soviet Union had a democratic system.
 B. Both the United States and the Soviet Union had a democratic system.
 C. Both the United States and the Soviet Union had a single-party system.
 D. The United States had a democratic system, and the Soviet Union had a single-party system.