The significance of the Dred Scott v Sanford Supreme Court decision is that it determined that just an enslaved person reaching a free state did not make them legally free. This decision reinforced and solidified the institution of slavery in the United States. It also declared that African Americans, whether enslaved or free, could not be U.S. citizens and therefore could not sue in federal court. Additionally, the ruling invalidated the Missouri Compromise of 1820, which would have restricted the expansion of slavery into certain areas. Ultimately, the decision further heightened tensions between slave states and free states, contributing to the lead up to the American Civil War. None of the options mentioned in the question is correct.
