Between 1972 and 1981, Texaco sold gasoline to independent Texaco retailers at "retail tank wagon prices" but granted substantial discounts to distributors Gill and Dompier. Gull resold the gas under it own name. Dompier resold the gas under the Texaco brand name to retail stations and entered the retail market directly. Since neither Gull nor Dompier had significant storage facilities, both distributors picked up gas directly from the Texaco plant and delivered it to their retail outlets. As a result, the sales volume increased substantially at the retail outlets. As a result, the sales volume increased substantially at the retail stations purchasing gas from these distributors, while independent Texaco retailers suffered a corresponding sale decline. In 1976 independent Texaco retailers file suit against Texaco. In 1990, the Supreme Court of the United States found that Texaco had indeed violated antitrust law. Which law do you think Texaco was found guilty of violating?