What was the major cause of african american migration from the rural south to northern cities during world war i?

Plz which of the following provisions of the compromise of 1850 was designed to appeal to slave states? a. congress passed a strict fugitive slave law. b. the slave trade was banned in washington dc. c. texas agreed to give away some of its land so that the territory would be available for future states. d. california was admitted to the union as a free state.