The correct options are
A Racial discrimination
B Inequality
D Racial segregation
African-Americans faced a lot of racial discrimination in the American society, were denied equal rights as that of the white Americans, and were segregation in public places. These problems emerged as points of struggle in the Civil Rights Movement led by Martin Luther King Junior.
Slavery had been abolished by 1865, so it was likley not a grievance in the 1950s.