Johnson is a volunteer fireman for Prince George's County

Johnson is a volunteer fireman for Prince George's County. One evening,

he responds to an alarm at a residence. Outside the house, Bob grabs Johnson by the shoulders and says: My little daughter is in the house. Please save her! I'll pay you $20,000.00 if you get her out alive!  Johnson bravely rushes into the burning house and rescues the little girl. The next day, Johnson finds Bob and asks for his check. Bob refuses to pay. Under these facts:
(A) Johnson will lose based on the theory of preexisting duty.
(B) Johnson will lose based on the theory of past consideration.
(C) Johnson will be awarded the money based on the theory of ordinary contract law.(D) Johnson will be awarded the money based on the theory of necessity.