Final answer:
The setting described covers great distances and explores other worlds or times, which best corresponds to oceans, making b) Oceans the correct answer.
Step-by-step explanation:
The correct answer to the question about a setting that is vast in scope and could cover great distances, possibly even visiting the underworld, other worlds, or other times, is b) Oceans.
Oceans are vast bodies of water that can serve as settings in literature where characters embark on widespread adventures and possibly explore different realms or eras, reflecting the boundless nature of the story's setting.
While forests, mountains, and deserts can also represent large areas, the mention of potentially visiting other worlds or times suggests a scope beyond what these options typically convey.
Oceans, being immense and mysterious, better fit the description of settings that allow for a wide range of fantastical explorations.