Toward the end of the civil war, what did general Sherman's special field order number 15 do?

B. It gave 40 acres of land and a mule to freed African Americans

Explanation:

Special Field Orders No. 15 confiscated 400,000 acres of land in a coastline strip, from Charleston, South Carolina to Jacksonville, Florida, and divided it into parcels of around 40 acres. Those parcels were given to around 18, 000 formerly enslaved African Americans.

Later Sherman made an order that army lends the mules to the families as well, as they can carry the burden and be used for plowing

This event was the basis for the famous slogan "forty acres and a mule".