The correct option is B.
Jackie could not believe that Nora can act so religiously. He knows her sister to be a loud person and he considered her to be a worst sinner than himself, so he find it quite unbelievable that her confession only took a few seconds and she was acting as if she was a saint. Jackie considered his sister to be a hypocrite.
It allows the reader to see how the character came to be who he or she is currently, it creates realism in the text, it creates tension between the narrator and the character, etc.
"you are your most valuable asset...YOU are the best thing that you have" this pops into Brian's mind when he becomes overwhelmed
