1. Mary offered to sell Mike several pieces of rare Chinese art at a very good price because they were duplicates in her own collection. Mike could not accept the offer at that time, but he did give Mary $500 in return for her promise to keep her offer open for three weeks. Mike returned with the agreedupon balance two weeks later to find that Mary already had sold the pieces she had offered to sell to him. Mary explained that she had been able to get a better price from another buyer. She offered to return Mike's $500 and insisted that this was all she was obligated to do. Decide