Answer:
One way to think about theme is letter c. a theme is an insight that the story reveals about human nature.
Explanation:
In literature, theme is the message underlying the literary work, the idea or meaning the author wishes to convey, be it in a direct or in an indirect way. When it comes to narratives, the theme is developed through plot events, characters’ actions, thoughts, and dialogs. In other words, the theme is a perception, an insight offered by the author, concerning human nature as well as the influences of culture and society in people's decisions and behavior.
For example, in the famous novel "The Great Gatsby", by F. Scott Fitzgerald, one the main themes is the degradation of society. Through the eyes of the narrator, we watch how the upper class loses its capacity to empathize. While the wealthy try their hardest to keep their own skeletons hidden in closets, they are quick to judge anyone that they consider inferior.