Answer: The correct answer is : of public labor unions.
Explanation: The Sacco-Vanzetti trial symbolized fears of red fear. During the red scare immigrants like Sacco lied to the police because they feared they were deported to their home country. Many people in the United States supported Sacco and Vanzetti because they thought they had not had a fair trial. These two Italian immigrants were accused of robbery in a factory where the security guard died. Despite protests in Europe over his conviction, they were finally executed in the electric chair.