Hill and Terrell owned two adjacent lots together. They sold one tract to Dr. Bowman. Their agreement provided that when Hill and Terrell paved their parking lot, Bowman would also pave his adjacent lot so that the parties would have one large interconnecting parking lot. After the agreement was made, Hill and Terrell sold their lot to a buyer, who constructed a building where the parking lot would have been. Bowman then sued Hill and Terrell, claiming that they had broken their contract. Are Hill and Terrell liable for breach of contract? and why or why not?