Which American social reformer was a key figure in the women's suffrage movement?

The key figure in the women's suffrage movement among the given choices is Susan B. Anthony. She was instrumental in advocating for women's right to vote and played a crucial role in organizing efforts for suffrage. Along with Elizabeth Cady Stanton, she co-founded the National Woman Suffrage Association and traveled extensively to campaign for women's rights. Anthony's dedication included organizing rallies, giving speeches, and lobbying lawmakers, which helped raise awareness and support for the suffrage movement.

While both Sojourner Truth and Elizabeth Cady Stanton made significant contributions to women’s rights, and Frederick Douglass was a strong ally for the cause, Anthony's specific focus and tireless work primarily centered on securing the right to vote for women, making her a prominent figure in this specific movement. Her legacy continues to be celebrated for its profound impact on gender equality and social reform in the United States.