Answer:
C. Exclusion from public school system is the correct answer.
Explanation:
The migration in which around six million African Americans migrated out of the southern united states to the Northeast, Midwest and west is known as Great Migration. The main reasons for their migration was lack of jobs and Racism in southern states. The new great migration occurred in 1960's when lots of African Americans moves backed to south due to De-industrialization in Northeastern and Midwestern cities. Exclusion from public school wasn't one of the prime reason for the migration.