Lindbergh-Sikorsky Aircraft Corporation e-mailed an offer to Kenneth Hiebel, the owner of the Triple R-Bar Ranch in Idaho. The e-mail stated, "Please consider this our offer to purchase 20,000 acres of your 61,200-acre ranch land near Harrington, Idaho. Our offering price is between $60,000 and $65,000 per acre. Please respond soon." Look at the requirements of an offer and determine whether the e-mail quoted above constitutes a valid offer. Explain.