Answer:
I would believe the answer is D
Step-by-step explanation:
The whole cause of the civil war was due to slavery and due to the United States defeating the Confederate States they created the 13th Amendment on January 31, 1865, and ratified by the required 27 of the then 36 states on December 6, 1865, and proclaimed on December 18. It abolished slavery in the United States, and now, with the end of the war, four million African Americans were free.
I hope this helps have a great day and happy holidays :)