To establish setting and context
Answer:
Some of Mexico’s rivers are the Grijalva, the Usumacinta, and the Conchos.
The point of view is different. You have consider every character. It’s unlikely that you mass descriptions (other than narrators), because you have keep readers interested by making it concise but eventful, while with books you have more flexibility and room to breathe.
Answer:
It's probably B. The oiler the best answer