In 1790 there were six slave states; in 1860 there were 15. ·from 1790 until congress banned the importation of slaves from africa in 1808, southerners imported 80,000 africans. ·by 1860 approximately one in three southerners was a slave. which event played the greatest role in creating these conditions in the south during the antebellum era?

Athe northwest ordinance of 1789
Bthe dred scott decision of 1857
Cthe secession of south carolina in 1860
Dthe invention of the cotton gin by eli whitney in 1793