Marion Purchased a Digital Camera,paying with a Promissory Note

Marion purchased a digital camera,paying with a promissory note.The note stated that Marion promised to pay $300 (the purchase price of the camera) in 10 monthly installments of $30 plus interest.Payments are due on the first day of each month,starting in January 2010.The interest is to be calculated as "three percent over the Chase Manhattan Prime Rate." Is this instrument negotiable?

A) No,because the future prime rate is not known at the time of the making of the note.
B) No,because the note does not describe a fixed amount of money to be paid.
C) Yes,because the variable rate of interest is calculated by reference to an index.
D) Yes,because the future prime rate is known at the time of the making of the note.