Find incorrect part

1. Many of the poetry of Langston Hughes explores the ability of African Americans to endure

---A---- --B-- ---C---

great social injustices


I guess Ans. is C, but I can't correct it, since I don't know how to analyze it.

How to do it?

C is fine. Try again. It is a problem of countability.
Teachers: We supply a list of EFL job vacancies
A Many-->much?
That's right-- 'poetry' is uncountable.