Mid-Americаn Oil hаd а cоntract with NSB Cоmpany tо supply 1,000 gallons of oil by September 1. The contract contained a provision that required all modifications to be written and signed by the company presidents. In early August, an executive of Mid-American talked with the purchasing agent of NSB who orally agreed to two shipments of oil; one in September and the second one in December. By September 30, when only 500 gallons had been delivered, NSB sued. The likely outcome of this lawsuit is: