I am here to help Sergeant!
Each guide was helpful, but we forgot to thank them.
You should use the plural pronoun, because we don't know whether the guides were only males, or females, or whether there were both sexes.
Answer:
A
Explanation:
It means intense pain in this context because the animal might be injured and in pain.
If there is a selection of answers I would go with
Repetition
Parallelism
maybe some others but I don't know all the poetic devices you have to chose from
