How did the Dred Scott case affect the division of free and slave states?

i got you ;)

Explanation:

They ruled that African Americans, whether they were slaves or had ancestors who were slaves, had no legal view in court. They felt that the Missouri Compromise was unconstitutional. In the eyes of the court, Dred Scott had no legal right to request his freedom

if that doesnt help then this aswell

The Dred Scott Decision outraged abolitionists, who saw the Supreme Court's ruling as a way to stop debate about slavery in the territories. The divide between North and South over slavery grew and culminated in the secession of southern states from the Union and the creation of the Confederate States of America

i beleive that d is the right answer