On April 1, Gina mailed Oscar an offer to buy his home. Oscar received the offer on April 5. On April 6, Oscar deposited a properly addressed, stamped acceptance in the mail. Gina received the acceptance on April 10. On April 8, Gina changed her mind, and she personally delivered a written revocation of the offer to Oscar. In most states: (A) A contract was formed on April 5. (B) A contract was formed on April 6. (C) A contract was formed on April 10. (D) A contract was not formed.