The Red Scare was a response to the Russian Revolution. The correct option among all the options given in the question is option "c". The Red Scare was in response to the Bolshevik
Revolution that had taken place in Russia in the year 1917. The Red Scare
happened between the years 1919 and 1920. The Red Scare got amplified by the
nationalism generated by World War I. Many American people were shaken by the
fear that such a revolution could start any time in America.
