Mo inherits a Bentley T Series 2000 car from his late grandfather. He advertises the car for sale in an online magazine for $30,000 and gives his phone number. Nat sees the advertisement and calls Mo stating that he will buy the Bentley car at the price stated. Mo replies, "The car is valued by experts to be worth $40,000. You will also have to pay an additional $5,000 for the restoration of the car stereo." Upon hearing this, Nat says "Oh." and hangs up. The next day, Mo leaves a voice message as follows, "Look, I need the money. Forget what I said earlier. Will you buy the car for $30,000 without the car stereo? Let me have your reply no later than 5pm today. If I do not hear from you, I will consider the Bentley sold to you at that price." Nat does not reply. Two days later, Mo finds out that Nat bought a same model car from a second-hand car dealer for $48,000. He alleges Nat has broken their contract.

Advise Mo on his legal position in this matter.