1. If my memory serves me well there were in about 350 000 African Americans who served in World War I. The huge part of them served as support troops. Only some of them fought alongside French army. According to this, the most suitable answer is: D. They served mostly in noncombad roles.
2. The Selective Service is the independent agency in the US which is used to maintain the information about those who is military conscripted. The Selective Service was designed to institute a draft to increase the number of men in the military. They provide all the names who registered to a military conscription to JARMS.