Bill's Car Broke Down on a Dark, Rainy Night

Bill's car broke down on a dark, rainy night. Along came Andy in his service station's four-wheel drive truck with tools and supplies in the back. Bill didn't have any credit cards and only $3.25 cash, so Andy told him to write a check or an IOU. Neither Andy nor Bill had any paper, so Bill wrote on the cover of Andy's lunchbox: "If my car is fixed right by Andy Walcott, I will pay him $150. (Signed) Bill Boyd." Andy indorses the note and takes it to a commercial factor for negotiation. The factor refuses, saying it is non-negotiable because it:

A) is written on a lunchbox.
B) is conditional on satisfactory repair of the car.
C) mentions the existence of a contract to repair the car.
D) was written in a situation of duress.