Cody offered to sell certain land to Daniel for $50,000, by a letter, which was signed by Cody. The letter specified that the deal was to be closed by Nov. 1, 2001, and that the entire payment was to be in cash. Daniel sent a letter saying that he accepted the offer, but his letter also stated that payment was to be made one-half at closing and one-half 30 days later. As of March 2002, Cody had not responded. Discuss in detail whether there is a valid contract between Cody and Daniel.