Answer: The Nineteenth Amendment
Susan B. Anthony was a famous American suffragist and social reformer. "Suffragists" or "suffragettes" were women who defended women's right to vote. Susan B. Anthony was pivotal in the movement. Along with Elizabeth Cady Stanton, she founded the New York Women's State Temperance Society, the Women's Loyal National League, the American Equal Rights Association, a women's rights newspaper called The Revolution and the National Woman Suffrage Association.
Their actions were pivotal to the eventual ratification of the nineteenth amendment (1920). This amendment prohibits the states and the federal government from denying the right to vote to citizens on the basis of sex.