please explain

For a-d we simply don't have support for them in the passages. The authors tell us nothing about length, the authors intent to create art or merely entertain (and I don't think there needs to be a distinction between those), and the authors seem to agree there is a good reason for scholars to think about genre. D is wrong because the authors done make a value judgement as to a works literary value as it relates to its genre. E is correct because the authors agree the genre doesn't come from formal elements or plots, but from the ways that readers engage with the material.