Taking into consideration that Hughes wrote during the Harlem Renaissance (a racial-conflict and racial-pride centered movement) to highlight the problems and importance of African-American people of the era, we can infer that, by daybreak, he is making a metaphor to compare the hopeful future he aims for with the break of the morning. He goes on to say that, when he becomes a composer, he will write songs that will touch everyone and will create unity to see the daybreak in Alabama.
Therefore, your best answer is option D.