Which of the following is true regarding african american participation in the civil war? select one: a. since african americans had been in the military for many years, a large group were able to advance in the ranks. b. over 400,000 african americans enlisted in the confederate army to fight against the union. c. there was little debate over the using of african american troops in the civil war in the north or south. d. the union army enlisted 200,000 african americans to fight against the southern armies.