Answer:
The correct answer is A. A collapse in diplomatic negotiations at Postdam led to the beginning of the Cold War between the Soviet Union and the US.
Explanation:
The Potsdam Conference was the third and last official meeting of the leaders of the "Big Three" - the three largest powers of the anti-Hitler coalition in World War II. The conference was attended by President Truman, Iosif Stalin, and British Prime Ministers W. Churchill (until July 25) and C. Attlee (from July 28). The Potsdam Conference took place after the victory over Nazi Germany and in anticipation of the USSR entering the war against Japan to develop a post-war program of peace and security in Europe and the world as a whole. The conference was held from July 17 to August 2, 1945.
Potsdam recognized the democratic principles of establishing peace and security in Europe: the main condition for security on the European continent was to prevent the revival of German militarism, and relations between states should be based on the principles of sovereignty and national independence, equality and non-interference in internal affairs.
The Potsdam Conference recognized the new balance of power in Europe and around the world, and outlined the contradictions between the Allies in World War II, which soon spilled over into the Cold War.