Mr. A makes an offer to Mrs. B on the 12^th of October. MRs B. pays an option agreement to keep the offer open to the 25^th. On the 15^th MR. A revokes the offer. Mrs. B accepts the offer on the 20^th. Which of the following statements are true.

1. A legally binding contract is never created
2. A legally binding contract is formed on the 12^th
3. A legally binding contract is formed on the 15^th.
4. A legally binding contract is formed on the 20^th.