Factors that Pulled African Americans to the North
2 reasons

Racism and economic troubles.

Explanation:

These are the elementary reasons for the migration of African Americans to the north. Segregation was very pronounced in the South. A huge number of African Americans have experienced some discrimination in the South. A large number of that population were lynched, so living conditions were impossible. In such circumstances, economic reasons were the cause-effect relationship. A society that discriminates against the population because of skin color did not provide even the minimum economic conditions.

just finished this it is b. centrifugal force

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.