Owner listed his house with Penelope, a real estate broker, granting Penelope an exclusive right to sell Owner's house. Penelope entered into negotiations with Buyer, who seemed interested in purchasing the property. Buyer found the price agreeable, but he insisted on including in the sales contract a clause giving him the right to cancel the contract if he could not get a loan to finance his purchase. At the closing, Buyer exercised his right to cancel, giving as his reason inability to procure a loan. Penelope turned to Owner and claimed that she was entitled to her commission even though the sale did not go through. Must Owner pay Penelope a commission?