A chef purchased the front portion of the land needed for a restaurant he desired to build and operate, but the back portion was the subject of a will dispute between a sister and brother. The sister's attorney advised that her claim was doubtful. The chef, knowing only that the unresolved dispute existed, agreed in a signed writing to pay the sister $6,000, payable $1,000 annually, in exchange for a quitclaim deed (a deed containing no warranties) from the sister, who promptly executed such a deed to the chef and received the chef's first annual payment. Shortly thereafter, the probate court handed down a decision in the brother's favor, ruling that the sister had no interest in the land. This decision has become final. The chef subsequently defaulted when his second annual installment came due.In an action against the chef for breach of contract, the sister will probablyA. lose, because she was aware at the time of the agreement with the chef that her claim to the property quitclaimed was doubtful.B. lose, because she suffered no legal detriment in executing the quitclaim deed.C. win, because the chef bargained for, and received in exchange, a quitclaim deed from the sister.D. win, because the chef, by paying the first $1,000 installment, is estopped to deny that his agreement with the sister is an enforceable contract