How did emigration to industrial jobs in the north during world war 1 affect the united states economy?

Question: How did emigration to industrial jobs in the north during world war 1 affect the United States economy?

Options:

The correct answer is:

Explanation: The Great Migration during WW1 was a change of homes for African American migrants from Southern farmlands to the urban cities of the industrialized North. Because of WW1, there was a shortage of labor in the northern factories. Millions of young men went to Europe to fight so factories and industries boomed and needed workers. Employers needed African-American workers to fill jobs so they would send agents to bring them North. African Americans were very hopeful and eager to leave their low-paying jobs in the rural South to go work in the North. It is estimated that between 300,000 and 500,000 migrated during this time.        

d) all choices are correct