The first african americans who fought for the union during the civil war

i already know its not a or

were told they would be freed after the war.
were usually led by african american officers.
had been recruited in border states.
were paid less than white soldiers.

Correct  Were paid less than white soldiers.

Details:

According to a National Archives article on "Black Soldiers in the U.S. Military during the Civil War" -

In 1864, however, the US Congress corrected the problem of unequal pay, and made the measure they passed retroactive, so that black soldiers would receive retroactive wages to compensate for that previous inequality.  

1 a

2 c

3 c

4 b

5 a

hope this

president thomas jefferson commissioned the expedition shortly after the louisiana purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an american presence in this territory before britain and other european powers