4. Parktown Realty Inc developed an upscale condominium complex. On October 1, Miranda Wine signed an offer to purchase one of the units. Part of that document said, "This offer is irrevocable by the Purchaser until one minute before midnight on the fifteenth day after its date, after which time if not accepted, this offer shall be null and void." As both parties were aware, the real estate market was highly volatile at the time that Miranda signed her offer to purchase. In the preceding months, prices had gone up and down, quite unpredictably. On October 10, Parktown signed that document with the intention of accepting Miranda's offer. Because of an oversight, however, the company did not mail the signed document back to Miranda until October 14. Miranda eventually received the letter on October 20. By that time, the real estate market had collapsed and she was no longer interested in buying a condominium unit at the original price. She therefore insists that her offer lapsed before it had been turned into a contract by Parktown's acceptance. Is she correct?