The correct answer is Ethel and Julius Rosenberg.
Here is why the other answers are incorrect.
Joseph McCarthy was a US Senator focused on exposing communists in American society. His actions help sparked the House Un-American Activities Committee, which lead to innocent citizens being blacklisted by Congress.
Sacco and Vanzetti were two Italian immigrants convicted of murder. However, the lack of evidence caused citizens to believe that these individuals were wrongly convicted/executed due to their political belief in the system of anarchy.
Elizabeth Gurley was a woman's right activists and also helped in the development of labor unions during the World War I era.