John's Repair Shop Has Fixed a Stereo

John's Repair Shop has fixed a stereo. The customer wants to take the stereo and pay for it in thirty days if the repair work is satisfactory. Which of the following is true?

A) John's has the right to keep the stereo until the customer pays for the repair.
B) John's can't keep the stereo, but must release it and sue on the contract if the customer doesn't pay.
C) John's must let the customer take the stereo and try it out to see if the repairs are satisfactory.
D) John call see the stereo if payment is not made within three days.
E) Both B and C