When Jeff's car breaks down, he asks Kwik Tow, Inc., to tow it from its location to Loyal Repair Shop. There is no discussion of a price, and Jeff and Kwik do not sign any documents. After the tow, Kwik sends Jeff a bill. With respect to Jeff's obligation to pay the bill, this is:
a) an express contract.
b) an implied contract.
c) a quasi contract.
d) no contract