A theme is a central idea or underlying message in a story. The statement "The main character of the story is a ten-year old boy named Troy" provides a specific detail about a character but does not convey a broader message or idea that can be considered a theme.
To illustrate, a theme might be expressed as "the journey of growing up" or "the importance of friendship." If you have additional statements or options, I’d be happy to help identify which one represents a theme!