Which of the Following Factors Contributed to the Great Migration

Which of the following factors contributed to the Great Migration?

A) the lack of sharecropping opportunities in the South;the improvement of sharecropping conditions in the North
B) an increase in European immigration to the South following WWI;job shortages in the South
C) a decrease in Jim Crow segregation in the South;wage equality in the North
D) job shortages in the South due to a decline in the price of cotton;job vacancies in the North due to a decrease in European immigration