What cause did Susan B. Anthony primarily advocate for?

Susan B. Anthony is primarily known for her tireless advocacy for women's rights, specifically the women's suffrage movement, which aimed to secure the right to vote for women. She co-founded the National Woman Suffrage Association and traveled extensively to speak on the importance of women's voting rights, emphasizing the need for equality and justice. Her dedication to this cause was so profound that she played a key role in elevating the issue of women's rights in public discourse during her lifetime.

While the other options pertain to important social issues, they do not align with the primary focus of Anthony's activism. Environmental protection, labor rights, and the fight against the death penalty, although significant, were not the central causes she championed. Anthony's legacy is firmly rooted in her efforts to secure equal rights for women, making this choice the most accurate representation of her advocacy work.