Answer:
b. dred scott vs sandford
Step-by-step explanation:
The correct answer is letter b.
It happened in 1857, when Dred Scott, an enslaved black man, whose owners had taken him from a slave-holding state to a slave-free state and then brought back to the slave-holding state. With this, he argued that since he was taken into free territory, he was legally free by the Constitution. The US supreme court then ruled that the constitution was not valid to a black person :(