Answer: The correct answer is: D. to plumber who has been convicted of robbery before but who is innocent in this case.
Peterson's wife opens the goose to cook it and inside it there was a big blue carbuncle, which was a very expensive gemstone that had been stolen from the Countess Morcar, but an inspector from Scotland Yard stopped a man who is a plumber who did a job in the countess's bathroom and he is suspected, but Scherlock discovers new clues that lead him to the real culprit of the robbery.
