Marteen,Inc

Marteen,Inc.sold several wood-working machines to Crown Doors,taking a security interest in the machines.Crown defaulted on the loan.Marteen repossessed the machines.Marteen would like to retain the machines to use as models.Which of the following statements is correct?

A) Marteen must notify the debtor that it intends to retain the machines and give Crown 20 days to object.
B) By taking possession, Marteen automatically foreclosed on the collateral. Marteen has valid title and need do nothing else.
C) Since the machines are equipment, Marteen cannot retain them. Marteen must dispose of the collateral in a commercially reasonable manner.
D) Marteen can retain the machines but must pay Crown the surplus, the difference between the fair market value of the machine and the amount of the debt.