Contractor agrees to repave your driveway for $$5,000.$ It is an extremely hot day, and half way through the job the Contractor says to you $"$My workers are overheated and we cannot work them this hard in this heat. But I can give them more work breaks, but I will have to pay some overtime to finish the job. However, if you pay me $$6000$ instead, I can complete the job as promised." This was the last day you could get the job done, as you were selling your house and had to repave it as part of the condition of the sale. You agreed to give him the preprinted check for $$5000$ today and pay the extra $$1000$ within a week. You move and forget about the extra $$1000,$ and Contractor sues you for the extra $$1000$ in court. Your best defense in court to not pay the extra $$1000$ is:

Group of answer choices

You thought his new terms were a joke

Mailbox rule

Mirror Image rule

Pre$-$existing duty rule