The Main Idea Behind the "Domino Theory" Was That __________

The main idea behind the "domino theory" was that __________.

A) the loss of one nation to Communists would lead to neighboring nations also falling to Communism
B) CIA covert interventions were the key factor in replacing the Soviet government in Moscow
C) countries where Communism was a threat had to be partitioned so Communism would not spread to other parts of that nation
D) the only way to stop Communism was through massive nuclear retaliation