Answer:
C but read below.
Step-by-step explanation:
B is never going to be correct. Slavery was never condoned by the constitution. The problem was that it was never prohibited either.
In its original form, D is true. The Emancipation Proclamation did apply only to the southern states. Later on in Dec. 1865, the 13 Amendment was passed and it made servitude of any kind prohibited -- at least that was the intention. D is incorrect.
E: As far as I know, reparations was never offered to former slaves.
It seems to me that A and C are saying the same thing. The Supreme Court was needed to make C true, but it was a matter of interpretation. The people writing the 13th intended any kind of slavery (involuntary servitude in any form is the wording of the 13.)
I think I would pick C but don't be surprised if A turns out to be the right answer. I don't think the constitution helps with the question of racial equality, but the person making the question may think it does.
Edit
The 13th did not stop the practice of segregation. That battle was hard fought in the 1960s. I don't think African Americans thought of themselves as equals -- otherwise the civil Rights movement was fought for a cause beyond my understanding.