Final answer:
Sarah and Angelina Grimké (option b) , daughters of a South Carolina slaveholder, strongly advocated for abolition and women's rights. They were among the first American women to speak publicly against slavery and for gender equality, and they did so by sharing their own experiences and knowledge.
Step-by-step explanation:
The two daughters from a South Carolina slaveholding family who urged abolition in the South were Sarah and Angelina Grimké. These sisters played a crucial role in the movement to end slavery, as well as fighting for female equality. They were born into a prosperous family that held slaves, but they were repulsed by the inhuman treatment of slaves, prompting them to join the abolitionist cause. Their substantial contributions included not only sharing their personal experiences and insights on Northern lecture tours but also advocating for women's rights by making direct comparisons between the oppression faced by slaves and by women in the United States.
Sarah and Angelina Grimké became Quakers and outspoken abolitionists following their estrangement from the South. Angelina's letter to William Lloyd Garrison's The Liberator in 1837 marked a significant moment when she acknowledged the oppression of women through her involvement in the abolition movement. The sisters were pioneers in addressing mixed-gender audiences about such controversial topics, challenging societal norms during their time.