S, who wants to sell his car, runs into his friend B on the street. S tells B "I'll sell you my car for $5,000." B says that she is interested but makes no commitment. There is no further discussion of the car, and the two friends split up after a friendly chat. That afternoon, S sells his car to C. That evening, B calls S and states that she will take the car. S states that he is sorry, but he has already sold the car. As between S and B the most likely result is: