Answer:
D.
Explanation:
The region in which the black population was highest in 1820 was the Mid-Atlantic. The Mid-Atlantic is a region that is found between the Northeastern and Southeastern states in the US. The Mid-Atlantic region comprises of New York, New Jersey, Virginia, West Virginia, Delaware, Pennsylvania, Washington D.C. and Maryland.
The high number of blac population were found in these states of Mid-Atlantic in 1820 as the whites had large number of black slaves in these states.
Therefore, option D is correct.