This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Physiology
Following constitute dietary fibers except 
Select and explain. 
A. Pectin, B. Cellulose, C. Hemicellulose, D. Riboflavin
D: Riboflavin
Answer: D: Riboflavin 
Explanation: Ans. (d) Riboflavin(Ref: Guyton, 13th ed/p.842)Classification of dietary fibersWater insoluble/less fermentedWater soluble/well fermented* Cellulose* Pectins* Hemicellulose* Gums* Lignin* Mucilages