I'm inferring that the answer is C because in the passage it states "I held on to my unforgiveness in the hopes that by drinking this poison I might kill my enemy." basically stating that she was holding a grudge against this person and she hoped that it would hurt them, then she proceeded on stating "But soon it was my insides that were burning.". metaphorically speaking her insides weren't actually hurting from any "poison", she is basically saying that she was the only one who was hurting from holding this grudge. I'm inferring that it is C because that answers makes the most sense.
