When John Lacey's car was stolen, he lodged a complaint with the police. The police were able to trace the car to a professional auto thief and returned it to John. When John got his car back, he realized that the thief had installed a new engine, changed the upholstery, and put a new stereo player in his car. The value of John's car is said to have undergone a(n) .

a. accession
b. arraignment
c. bailment
d. lien