*A broker obtained an exclusive listing to sell a piece of property. He spent much time, money, and energy. The seller refused to allow the broker to proceed under the agreement. The broker should:

a. consider the seller's refusal a breach and sue for damages.
b. consider the seller's refusal a breach and claim the amount of commission as liquidated damages.
c. ignore the seller and proceed.
d. relieve seller of liability, and work on improving relationship so as to enable retaining future business.