19. as its intellectual voice, became the leader of the harlem renaissance. a. f. scott fitzgerald b. h. l. mencken c. w. e. b. du bois d. claude mckay

The right answer is C. W.E.B. Du Bois.

The Harlem Renaissance was an art movement in the 1920s that focused on African-American art. It was centered around the Harlem neighbourhood in NYC, hence the name.

Let's look at all the answers:
A. - F. Scott Fitzgerard was also active around that time, but he was part of another movement, the "Lost Generation" of people who came to age during World War I, and were traumatised by it.
B. H.L. Mencken was in fact a racist, so he could not form part of a movement centered around African-American art.
C. W.E.B. Du Bois  was a civil rights activist, and in fact published and edited a lot of articles supporting and encouraring the Harlem Renaissance. This is the correct anwer.
D. Claude McKay creates a potential confusion here, as he also participated in the Harlem Renaissance, most notably with his book "Home to Harlem" in 1928. However, answer C is more fitting, as McKay mostly focused on literary work, and not an activist,  as Du Bois was.