【单选题】

According to the author, African-Americans filmmakers have failed to take which of the following steps in properly promoting African-American cinema
A．(A) They have failed to demonstrate to studio executives the market potential of their films.

B．(B) They have failed to express ideological issues in their films that could attract potential audiences.
C．(C) They have neglected to use genuine African-American music as a force in their films.
D．(D) They have exploited stereotypes about African-Americans for the gain of themselves, but not the genre.
E．(E) They have failed to depict the African-American experience in an artistically engaging manner.