7. Sepehr offered to sell Kolby his car and agreed to hold the offer open for one week, expiring Saturday at noon. The following Sunday, Kolby phoned Sepehr to tell him that he had decided to accept the offer and purchase Sepehr's car. Sepehr said at that time that he had decided to keep the car and was just about to phone Kolby to revoke the offer. Kolby said, "Too bad," and demanded performance of the contract. Explain the legal responsibilities of the parties and the outcome. [2 marks]