Identify the relevant issues, state the applicable principles of law, supported by authority, and apply the law to the given facts to arrive at a conclusion.

Scenario (the facts) John owns a Honda Civic car which he wishes to sell.

He emails Joan, who he knows is looking for a car, on 1st December: Would you like to buy my car? It is yours for $8,000.

On December 2 Joan replies: Great can I pay you $5,000 now and the balance of $3,000 in one months time?

John responds: I really need the $8,000 now as I need to purchase a new car.

On the evening of December 2 John receives an email from Donald: I hear you are selling your Honda Civic, I will give you $9,500 for it. Unless I hear from you to the contrary I will bring the cash and pick the car up at midday tomorrow.

As John is reading Donalds email he sees in his email box that he has a missed voicemail from Joan since he would rather sell the car to Donald whatever Joan says, he deletes it without listening to it.

The message Joan had left was as follows: Hi John, I understand, mum will advance me the other $3,000 so I will buy the car for $8,000 cash when can I collect it?

Required: On the basis of the law governing the essentials of a valid contract, explain whether John has a valid contract with Joan or Donald or neither or both of them Your argument, naturally, should be supported by appropriate legal authorities.