Considering the book's content, the theme of light in the darkness by tony diets is loneliness.
The book centered around Jozette and her family living in a isolated underwater domed city.
Throughout the book, it was revealed how Jozette constantly yearns to see what is above them, as she misses her mother, who had left for the water surface.
Hence, in this case, it is concluded they the correct answer is Loneliness.
Learn more about the theme of the novel here: https://brainly.com/question/25856097
