In Langston Hughes' poem “The Negro Speaks of Rivers,” the rivers serve as a powerful symbol that connects the speaker to the deep history and enduring culture of the African diaspora. Therefore, the best answer is:
D. They represent the deep history and lasting culture of the African people.
The rivers mentioned in the poem evoke a sense of ancient wisdom and continuity, representing the speaker's connection to the past and the broader narrative of African heritage. They are emblematic of the spiritual and historical journey of African people throughout time.