Which is a secondary source about civil war

What are the answer selection if there is any?

a Gettysburg Address

b movie about Gettysburg

c Union soldiers' personal letters

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.

. political or economical policy that isolates a country from participating in international relationships. it has been suggested that the united states participates in isolationism because of its lack of involvement in particular wars or alliances.