Yvonne offered to sell Tracy several pieces of rare Italian art at a very good price because they were duplicates in her own collection. Tracy could not accept the offer at that time, but she did give Yvonne $500 in return for her promise to keep her offer open for three weeks. Tracy returned with the agreed upon balance two weeks later to find that Yvonne already had sold the pieces she had offered to sell to her. Yvonne explained that she had been able to get a better price from another buyer. She offered to return Tracy’s $500 and insisted that this was all she was obligated to do. Is Yvonne right?