by reading the passage we can find certain clues that help us figure it out, examples include: "Hummel sighed" the mentioning of the name is rarely done from the first person, and "Caldwell decided as he walked away." this clears up that Caldwell is not narrating either. if no present character cannot be identified as the narrator the story is being told from the third person.
I had the same question and the answer was knowledgeable but you didn't give options so our questions might be talking about completely different passages
