Answer:
Option C, is the correct answer.
Step-by-step explanation:
On 6th March 1857, the supreme court of the U.S. in a case (Dred Scott v. Sandford) announced that a slave who is residing in the free state and region of the U.S. was not permitted to his freedom and that the African -Americans were not and could nevermore be subject of the citizenship of the U.S. Moreover, the Supreme Court declared that Congress does not possess any power to exclude slavery from various states of the U.S.