After what major event did the red scare start

A. After the cold war ended

B. During the great depression

C. During WW2

D. Following WW1

the answer is A: After the cold war ended

explnation: As the Cold War between the Soviet Union and the United States intensified in the late 1940s and early 1950s, hysteria over the perceived threat posed by Communists in the U. S. became known as the Red Scare. (Communists were often referred to as "Reds" for their allegiance to the red Soviet flag.)