Who was a prominent advocate for women's rights and co-authored the pamphlet "Letters on the Equality of the Sexes and the Condition of Women"?

The correct choice is Sarah Grimke, who was a notable advocate for women's rights and co-authored the pamphlet "Letters on the Equality of the Sexes and the Condition of Women." She, along with her sister Angelina Grimke, played a pivotal role in the early women's rights movement and spoke passionately against inequality. Sarah's contributions to the discourse on women's rights emphasized the need for legal and social equality, making her a prominent figure in the struggle for women's rights during the 19th century.

While Elizabeth Cady Stanton and Lucretia Mott are well-known for their significant roles in organizing the Seneca Falls Convention and advocating for women's suffrage, Stanton was not involved in the aforementioned pamphlet. Angelina Grimke, although influential in the abolitionist movement and women's rights, was not specifically co-author of that particular work. Thus, Sarah Grimke's connection to this pamphlet highlights her essential role in advocating for gender equality.