Answer:
Step-by-step explanation:
It sure wasn't D. They were slaves, bought and sold.
It didn't free the existing slaves in the United States. It made it illegal to import more people to be slaves.
The choice is between A and C.
I think you should pick C which was factually true and exactly what happened. In other words, the law was circumvented.
The problem with A is that it they were let in directly at the request of Georgia and South Carolina. These two states had very complex responses to the Jan 1, 1808 law. Their economies depended on as many slaves as they could get legally or not.