The correct answer is by way of ending segregation.
By ending segregation Truman's executive order of the 9981 is the one which affected the segregation.
Executive order of 9981 was termed as the executive order which was issued by president S. Truman in the year 1948.
This order abolished different discrimination which were made by armed forces of the United States, they included national origins, religion, and colour.
Before that order which was in 9981 made blacks who were in the military to work under different rules which made them to delay entry to their combat.
Within months of being qualified is the time when the whites will begin training but the blacks they had to wait before they could begin their combat for four years.