The correct answer is A) violence by anarchist groups.
The arrest of Sacco and Vanzetti on murder charges produced violence by anarchist groups.
Bartolomeo Vanzetti and Nicholas Sacco were convicted of robbery and murder in 1921. They were Italian-Americans radicals, and that affected their sentence. Their trial was held under the Red Scare years, where Communist persecution was at its best. The Red Scare was initiated by Wisconsin Senator, Joseph McCarthy. Both men continue to appeal but the final rejection came on April 9, 1927, and Vanzetti and Sacco were sentenced to death.