Answer:
Option B. Free African Americans were allowed to enlist in the Union army and navy.
Step-by-step explanation:
On September 22, President Abraham Lincoln issued what it is known as "The Emancipation Proclamation" in which he declare that as of January 1st, 1863, all the slaves in the rebellious states shall be forever free. The proclamation also authorized the recruitment of freed slaves and free African Americans as soldiers for the Union Army, and in fact, in the next 2 years almost 180.000 of them fought as member of the Union Army and Navy.