What benefits does douglass think blacks will derive from service in the union army

Douglass thought fighting in the army would bring freedom to the black and help them attain citizenship. As an academic and president advisor, Douglass held meeting with the president, esteemed politicians and influential friends to convince them to include black soldiers in the Union War to fight alongside white soldiers.

This he did by writing letter in journal and conveying public speeches. However, Douglass's request was denied since the president and the Union Generals feared that the white soldiers will refuse to participate in battles fighting alongside black soldiers.

they supported black codes so the answer is a or b

it would be a. that is the only one i could think of