E.I. DuPont de Nemours and Co. manufactures a special fiber that is used to make body armor, fiber-optic cables, and other products. In fact, DuPont controls more than 70 percent of the U.S. market for this fiber. DuPont imposes multiyear agreements on customers for the fiber, requiring them to purchase from 80 to 100 percent of the fibers they need from DuPont. This limits the ability of other producers of the fiber to compete. Do these agreements constitute monopolization and attempt to monopolize in violation of the Sherman Act? Explain. [E.I. du Pont de Nemours and Co. v. Kolon Industries, Inc., 637 F.3d 435 (4th Cir. 2011)]