Well reformation happened because of different religions and people thought these religions that you described are the best ones. This caused political conflicts and warfare
After world war 1 the United States wanted to isolate themselves from things like that because of how bad the war was. They went as far as to not join the league of nations that their President made himself with other presidents. After the Korean War, they decided to not isolate themselves and meddle as much as possible to prevent the spread of communism because it would strengthen the Soviet Union who was the main enemy.
Out of all of them, Switzerland would be the one that was neutral.
1. D. Iron Curtain
2. A. True
3. B. "NATO"