Buyer makes a written offer to Seller to purchase 100 dolls at $100 each. Seller responds by sending this writing to Buyer: "I accept your offer but the price of the dolls has increased to $150 each." Is Seller's communication effective to a contract between the two? (Assume for purposes of this question only that both parties have merchant status under the UCC.)

Buyer makes a written offer to Seller to purchase 100 dolls at $100 each. Seller responds by sending this writing to Buyer: "I accept your offer but the price of the dolls has increased to $150 each." Is Seller's communication effective to a contract between the two? (Assume for purposes of this question only that Buyer has merchant status under the UCC but Seller does not.)