Why is B wrong?

Hello @kassidee, I am not sure I would describe it as too vague, but your reassessment of answer choice B is exactly right. The author never says that the corrido is the only ballad form to use local language. There is simply no support for this, and I think it is safe to assume that there could be many folk ballads that use region-specific words. E is a better choice because the author has introduced a number of characteristics of the corrido. It is from a particular border region, sung in Spanish, simple/swift stories, few figures of speech, etc. The despedida may be an important characteristic, but it is not the only one. Even without it, the author would likely be able to identify a corrido.

The author also mentions that the despedida comes at the end of a ballad, while also inferring that many famous ballads are unfinished (in the beginning), and we can assume that these unfinished ballads were recognized