Black Northerners Did Not Initially Serve in the Union Army

Black northerners did not initially serve in the Union army during the Civil War for all of the following reasons EXCEPT

A) whites worried that blacks would use military service as a ground for demanding their rights as citizens.
B) blacks in the North refused to enlist in the military until the Union made the emancipation of southern slaves an official aim of the war.
C) white officers believed that blacks would make poor soldiers who would flee in the face of danger.
D) Lincoln worried that allowing blacks to serve might compel the Border States to secede.