a) The speaker is focused on a group of people and their history. This is the correct option.
James Weldon Johnson created the song to be sung in front of Lincoln during one of his birthdays ( 1900). Then, the song became part of an association, the National Association for the Advancement of Colored People , and since then it has been considered as a sort of Black National Anthem.
These options are not right:
b) The speaker is focused on himself and a particular event. ( James W. Johnson is focused on a social event. He is part of that social problem: racism).
c) The speaker is focused on his immediate family at a gathering. . ( The song was sung in one of Lincoln's birthdays. The song is not focused on the speaker's family).
d) The speaker is focused on a close friend and a shared experience ( The speaker is concerned with a social issue: racism in the U.S).