Olivia Contracts for the Sale of This Year's Strawberry Crop

Olivia contracts for the sale of this year's strawberry crop to Phoenix,with payment to go to Rural Cooperative Association.The contract reserves to Olivia and Phoenix the right to modify its terms.Rural Cooperative's right to payment is

A) not affected by the reservation.
B) subject to any change that Olivia and Phoenix make.
C) limited only if Rural Cooperative agrees to any changes.
D) terminated by the reservation.