D. is correct because there were people like Harriet Tubman who was an ex slave who repeatedly returned to the south to help the slaves. C. is true because Abolitionism was a growing factor in the North, the number of abolitionists grew as time went on, especially after the book "Uncle Tom's Cabin" was published by Harriet Beecher Stowe. I'd say that A. is the wrong answer because most slaves were found there, but everyone there needed the labor, so no one besides the slaves supported Abolitionism in the south, and no one cared about what the slaves thought because they could not own, or buy land, or do anything.
