english 9th grade ( The Cold War ) QUESTION

1.Which sentence contributes to the authors main idea in the informational text The Cold War?Stalin wanted to maintain control over these nations, which were on the western border of the Soviet Union.The Soviet Union had liberated several Eastern European nations (including Poland, Czechoslovakia, and Hungary) from Nazi rule toward the end of the war.The Berlin Wall prohibited the Communist eastern portion of the city from interacting with the capitalist western portion of the city.Minister Winston Churchill agreed that Japan must surrender unconditionally, and that Germany would be divided into four occupation zones administered by the Soviet Union, France, Britain, and the United States.