Racism Was a Particularly Important Incentive for Poor White Voters

Racism was a particularly important incentive for poor white voters supportive of the Democratic ticket in the South because

A) keeping black people as an underclass in southern society was important to poor whites' sense of self-worth and economic well-being.
B) poor southern whites had too often suffered the arrogant abuse from free blacks in Southern cities.
C) poor southern whites lacked the education to understand the true equality of people of all colors.
D) poor whites stood to gain economically from the plight of black Southerners.
E) All of these choices.