Answer: A. The abolitionist movement grew stronger.
Dred Scott v. Sandford (1857) was a landmark decision by the United States Supreme Court. It held that black people whose ancestors were imported into the U.S., whether enslaved of free, could not be American citizens. Therefore, they could not sue in federal court. Moreover, it ruled that the federal government had no power to regulate slavery in the territories acquired after the creation of the United States.
The decision was controversial, and greatly opposed by abolitionist groups. It strengthened the abolitionist movement and may have been a catalyst for the American Civil War.