What was the united negro improvement association best known for? . a. opposing black separatism. b. using federal legislation to end racism. c. advising blacks to 'cast down their buckets' where they were. d. performing charitable work for the african american community

I believe the answer is: D. performing charitable work for the African American community

United Negro Improvement Association was created in order to improve the quality of lives for African American citizens in united states, which might be stunted due to having to face centuries of slavery, racial segregation, and years of racial discrimination.

One of their main program is providing poor African American students with scholarship to pursue their education.