Which of the following statements about myofibrils is not correct? (a) Each skeletal muscle fiber contains hundreds to thousands of myofibrils. (b) Myofibrils contain repeating units called sarcomeres. (c) Myofibrils extend the length of a skeletal muscle fiber. (d) Filaments consist of bundles of myofibrils. (e) Myofibrils are attached to the plasma membrane at both ends of a muscle fiber.