Why Was the Enlistment of African Americans in the Union

Why was the enlistment of African Americans in the Union army and their deployment in battle delayed until 1863?

A) Most Union generals doubted that they would make good soldiers.
B) Abolitionists feared that the white officers would treat the black troops as disposable.
C) Lincoln feared that free blacks from the North would be captured and enslaved.
D) The Union did not have enough funds to equip and pay destitute black soldiers.