The literary device used in "a curious boy named Ethan" is b. Alliteration, as the repetition of the 'c' sound in "curious" and "boy" creates a rhythmic quality.
As for how the story might continue based on the exposition, a plausible option is a. Ethan discovers a hidden door in the woods. This choice aligns with the theme of curiosity and exploration suggested by the initial description of Ethan.