Hello again, I read this story last year! :)
So person vs environment means that man is struggling against the forces of nature.
Lets examine your answer choices and see which one fits that description:
A) No, this would be man vs man.
B) This is dialogue between the two men, you can cross this one out too.
C) Once again, this is man vs man.
D) This would be an example of person vs environment, because it brings up the dangers of the trees and shrubs. This is your answer.