The success of the Bolsheviks in Russia contributed to the post-World War I phenomenon in the United States known as
A) the Red Scare.
B) Roosevelt Corollary.
C) the ‘Last Generation’.
Eliminate
D) the Progressive Movement.

The success of the Bolsheviks in Russia contributed to the post-World War I phenomenon in the United States known as the red scare - a. 

The red scare was a "movement" or rather stream of thoughts which feared the consequences which would be brought upon the American society in the case when communism would prevail.