On a Thursday afternoon, David sends a letter to Tessa's work office with an offer to sell his car to her for $25,000. On Sunday, having changed his mind, David sends an email to Tessa's work email account, revoking his offer. Tessa does not go to her office over the weekend and does not learn about the revocation until Monday morning, just a few minutes after mailing a letter of acceptance to David. When Tessa demands that David sell his car to her as promised, David claims that no contract exists because he had revoked his offer prior to Tessa's acceptance. Is David correct? Explain.