On Thursday, Dennis mailed a letter to Tanya’s office offering to sell his car to her for $3,000. On Saturday, having changed his mind, Dennis sent a fax to Tanya’s office revoking his offer. Tanya did not go to her office over the weekend and thus did not learn about the revocation until Monday morning, just a few minutes after she had mailed a letter of acceptance to Dennis. When Tanya demanded that Dennis sell his car to her as promised, Dennis claimed that no contract existed because he had revoked his offer prior to Tanya’s acceptance. Is Dennis correct? Explain.