This idea is in keeping with the theme of the story that humans are?

Theme is a binding agent. It makes everything in a story stick together

To state its theme is one way of describing what a story is about. To start finding a story’s theme, see if there is a more or less generic concept that fits, like “reform”, “racism”, “good vs. evil”. The theme of Shakespeare’s Othello is jealousy.

the answer to "what does the narrator realize by the end of the story" is b.