Final answer:
Both the United States and the Soviet Union were responsible for beginning the Cold War.
Step-by-step explanation:
In my opinion, both the United States and the Soviet Union were responsible for beginning the Cold War. The Cold War was characterized by a series of actions and events that escalated tensions between the two superpowers. While the Soviet Union's expansionist ambitions and establishment of communist governments in Eastern Europe contributed to the start of the Cold War, the United States' policy of containment and attempts to prevent the spread of communism also played a significant role. It was a combination of actions and policies from both sides that led to the beginning of the Cold War.