D. African Americans and women.
Step-by-step explanation:
Although women were not involved directly in World War I, they worked exclusively on the home front. Women took many of men's jobs during World War I, since men were off fighting in the war. Women worked in factories, making weapons, vehicles, clothes, and ammunition for soldiers, along with caring for the children at home. Although the boom of working women really happened in World War II, with the iconic Rosie the Riveter poster, women were also important in World War I. African American women also took part in department stores and as elevator greeters, which was normally a man's job. African American men served in the military in segregated parts, normally in the infantry or the calvary.