In Blank v. Borden (1974) 11 Cal.3d 963, the Supreme Court examined a real estate listing agreement that provided the broker would be paid the full 6 percent commission if the owner withdrew the listing. (Id. at p. 966.) The court acknowledged it must look to the substance rather than form in determining the true function and character of an arrangement challenged as a voidable penalty. (Id. at p. 970.) The court then stated the listing agreement in question presented the owner with a true option or alternative. Specifically, the owner could continue the listing or could change his mind about selling the property, terminate the exclusive listing agreement, and pay the sum specified in the contract. The court concluded the payment required upon termination was valid because it did not have "the invidious qualities characteristic of a penalty or forfeiture." (Ibid.) In summary, a contract provision that provides a party with a true alternative performance--that is, an alternative that provides a rational choice between two reasonable possibilities--does not involve an unenforceable penalty. (Id. at p. 971.) The court concluded that a withdrawal-from-sale clause in a real estate broker's exclusive listing agreement which required the owner to pay the broker's commission after withdrawing the property from the market constituted a valid provision for alternative performance rather than a void penalty or liquidated damages provision. The court held that the key distinction between a contract providing for alternative performance and one for liquidated damages is that in the case of the former, "its terms in no sense contemplate a 'default' or 'breach' of an obligation by the owner upon whose occurrence payment is to be made." ( Id. at p. 970.)