When John Lacey's Car Was Stolen,he Lodged a Complaint with the Police.After

When John Lacey's car was stolen,he lodged a complaint with the police.After a while,the police were able to trace the car to a professional auto thief and return it to John.When John got his car back,he realized that the thief had installed a new engine,changed the upholstery,and put in a new stereo player in his car.Which of the following is true with regard to the new engine,upholstery,and stereo player the thief installed in John's car?

A) These improvements have to be returned to the thief.
B) These improvements now rightfully belong to John.
C) The improvements have to be paid for by John if he wants to retain them.
D) The improvements will be confiscated by the police.