Which u. s. strategies contributed to the fall of some communist countries? manifest destiny and the monroe doctrine deterrence and containment détente and the good neighbor policy collective security and isolationism

The first one is incorrect because both of those happened during the founding and growing of the U.S.

The second one is correct because the U.S. used different form of propaganda to scare people away from communism, which lead to the Red Scare. Also we successfully kept communism from spreading to many countries that were close to falling into that form of government with the method of containment. 

The third one is incorrect because the Good Neighbor Policy was toward the Latin Americas, not toward any communist state.

The fourth one is incorrect because we were not isolated in our foreign policy, which is why we entered the Cold War and won against communist Russia.

Hope this helps! 

Ibelieve the answer is answer 5