Read the excerpt below and answer the question. Certainly there is, for the American Negro artist who can escape the restrictions the more advanced among his own group would put upon him, a great field of unused material ready for his art. Without going outside his race, and even among the better classes with their "white" culture and conscious American manners, but still Negro enough to be different, there is sufficient matter to furnish a black artist with a lifetime of creative work. And when he chooses to touch on the relations between Negroes and whites in this country, with their innumerable overtones and undertones surely, and especially for literature and the drama, there is an inexhaustible supply of themes at hand. To these the Negro artist can give his racial individuality, his heritage of rhythm and warmth, and his incongruous humor that so often, as in the Blues, becomes ironic laughter mixed with tears.

What is the main idea in this excerpt from "The Negro Artist and the Racial Mountain"?

African American artists will run out of material to write about.
The topic of African American culture has been exhausted in literature.
There is still a lot to be written about the African American experience.
The African American experience is similar to the white American experience.