Hello!
Your answer is B. He is becoming less human and more like a bug
Not only is the entire book about a human becoming a bug, but him liking rotten foods more than fresh ones is not human nature.
This mostly suggests that Grete thinks her brother smells, or she has a sensitive nose. She opens the windows to try to get rid of the smell her brother brings into the room
According to the analyses of the stories you were asked to read, "A Pair of Silk Stockings" best represents literary realism. In realism, the most important thing of course is to be realistic as much as possible, and also human values and flaws are quite relevant, as opposed to feelings from Romanticism.
