1. Allison says to George, "I will sell you my
2. Nissan Pathfinder for $25,000. I will keep this offer open for 30 days in exchange for $500." George gives Allison $500 to hold the offer open. 1 week later, George sends a letter to Allison rejecting the offer because the car is too expensive. 5 days later, George wins a lucky hand at poker and sends a letter to Allison accepting the offer along with a check for $25,000. Was a valid contract formed?