C. All African Americans.
Step-by-step explanation:
The Dred Scott decision happened in 1857 and was the court ruling that stated African Americans, no matter if they were enslaved or free, were not citizens of the United States. Since they were not citizens of the United States, they did not have the right to sue in Federal court. An African American man, named Dred Scott, sued in Federal court despite him not being a citizen of the U.S. He ended up losing this court case, and it went down to be one of the worst decisions in Supreme Court history.