Answer:
D. an Infantry Regiment of African-American soldiers that served in World War I.
Step-by-step explanation:
The Harlem Hellfighters was an infantry regiment of the New York Army National Guard during World War I and World War II. Its official name was the 369th Infantry Regiment, and it was composed of African Americans. During World War I, this regiment spent more time in combat than any other American unit. They also suffered the most losses of any American regiment.