Which of the following statements about fiber is FALSE?

(a) The fiber in the diet slows the passage of food through the intestines.
(b) The cellulose of celery stalks and lettuce leaves is fiber.
(c) Fiber passing through the digestive system scrapes the wall of the digestive tract, stimulating mucous secretion, and aiding in the digestion of other molecules.
(d) Humans are unable to extract any caloric value from the fiber.
(e) Dietary fiber reduces the risk of colon cancer.