The result of the 1857 Dred Scott v. Sandford case in the Supreme Court was that Dred Scott was denied his freedom and remained a slave. The Court ruled that African Americans could not be citizens of the United States and therefore had no right to sue in federal court. The decision also declared the Missouri Compromise unconstitutional, asserting that Congress did not have the authority to prohibit slavery in the territories. Therefore, the correct answer from your options is:
Dred Scott returned to slavery.