Answer: The answer is D, the establishment of pro-Soviet governments in Eastern Europe.
Explanation: Winston Churchill was describing the establishment of pro-Soviet governments in Eastern Europe as an "iron curtain" falling across Europe. This term was used in a speech delivered by Churchill in Fulton, Missouri, on March 5, 1946, in which he warned of the dangers posed by Soviet expansionism and the need for a strong Western response to this threat. Churchill's speech marked the beginning of the Cold War and became a famous and influential call to arms against Soviet aggression.