Only one?
If one then cheerful
If two then gloomy and cheerful
They are all correct but A. Explains it the best
Harriet Tubman uses ethos to have the readers trust her and it helps make her an author you can trust. Ethos is when an author tries to convince the reader that they are a reliable source. So she uses ethos for her rhetorical appeal.
Hope that helps
It's known as abstract nouns
