A - to explain where in Mansfield the colored school was located B - To illustrate how badly Mansfield neglected black students
C - To illustrate how unfunded all schools in Mansfield were
D - To explain the concerns of community leaders

I can't say for sure but I think it I'd B

pan-africanism or pan-africanism is a political, philosophical, cultural and social movement that promotes african twinning, the defense of the rights of african people and the unity of africa under a single sovereign state, for all africans, both africa as of the african diasporas.