Moving towards Northern Cities is the right answer.
The Great Migration was the largest movement towards North America. One of the important cause for this movement was America's entry in the World War I which led to an increase in the demand for the additional labor in the war-related industries. Therefore, this increasing demand for labor was fulfilled with the supply of the African American labors. Industrial jobs that had not been previously accessible to African Americans were now open for them in great variety and quantity in the Northern cities. Hence the African Americans moved for better job opportunities