The correct answer is A. The first Red Scare.
After World War I, the United States was fearful of the spread of communism and anarchy. These fears were developed due to the revolution going on in Russia during World War I. This period became known as the first Red Scare.
Sacco and Vanzetti were part of this era due to their conviction and eventual execution. These two men were accused of robbery and murder. They were found guilty in court, despite a small amount of evidence being provided. Many Americans felt that the reason they were found guilty so innocently was due to their political views. Sacco and Vanzetti were anarchists, meaning they believed that society should have no government. Along with this, they were Italian immigrants. During this time nativism was on the rise and discrimination against immigrants was widespread.