What was the cause of the red scare?

A. a communist government came to power in China

B. McCarthy gave a speech accusing leaders of communism

C. membership in the communist party was illegal.

D. all of the above

The Bolshevik Revolution in Russia, which led many to fear that immigrants, particularly from Russia, southern Europe, and eastern Europe, intended to overthrow the United States government; The end of World War I, which caused production needs to decline and unemployment to rise.