Final answer:
Benjamin Banneker was the African American scientist who contributed to preventing soldiers from starving and participated in the design of Washington D.C.
Step-by-step explanation:
The African American man who was a scientist and helped prevent soldiers from starving, and later assisted in designing Washington D.C., is D: Benjamin Banneker. Benjamin Banneker was a renowned African American almanac author, surveyor, naturalist, and farmer. He played a critical role in surveying the land for what would become the nation's capital. Moreover, his almanacs included valuable information that was critical to rural agricultural communities.