The answer is D. the district of Columbia was closed to slavery.
Senator Henry Clay introduced a series of resolutions on January 29, 1850, in an attempt to seek a compromise and avert a crisis between North and south. As part of the Compromise of 1850, the Fugitive Slave Act was amended and the slave trade in Washington DC was abolished.
The answer to your question is,
Andrea del Verrocchio
-Mabel <3
The theory is called mercantilism.
