Which theme is reflected in “for a lady i know” by countee cullen?

It's (a), social class distinction, specifically social class distinction based on race. 

I’m not sure about that

A. they give the reader hope. if the whole book was dark & unhopeful it’d be a little less interesting, little moments make it more interesting to read because then you want to know what happens. if it’s all dark there’s no point in reading if you already know the outcome of it.