The correct answer is D. The Harlem Hellfighters were an infantry regiment of African American soldiers that served in World War I. If you want to find more information about the Harlem Hellfighters, you can conduct a search using a search engine like Google. Simply type "Harlem Hellfighters" into the search bar, and you will find various sources such as articles, books, and websites that provide detailed information about this historical regiment. Some reliable online sources to consider include reputable news outlets, academic institutions, and historical archives.
