On June 1, Buyer sent a purchase order to Seller for 1,000 widgets at $10 each. The purchase order stated 'delivery by June 30'. On June 3, Seller sent an acknowledgment form that stated, 'We accept your order. Delivery will be by July 15.' Buyer did not object. Under UCC Article 2, which of the following is correct?

Under UCC §2-207 (Battle of the Forms), a definite expression of acceptance operates as an acceptance even if it states terms additional to or different from those offered. Thus, a contract IS formed. Between merchants, additional terms become part of the contract unless they materially alter it. A change in delivery date is generally considered a material alteration. Therefore, the new date is a proposal that does not become part of the contract unless expressly agreed to.