Mark, the owner at Owen Bed & Breakfast Hotel offered to sell his hotel to a friend, Zed for 350,000. Mitch, expressing 'acceptance' in writing at a price of 300,000, which was rejected by Mark. Then Zed decided to pay the full price the next day and contacted Mark, but Mark decided not to proceed with the sale. Zed believed there is already a valid contract since he had accepted Mark's offer in writing. Advise Zed as to his rights in contract law