Ans. is 'b' i.e., LactuloseDietary fibres (Review) Dietary fibre consists of unabsorbable cell wall and other consititutents of vegetable food like celluloseQ, lignin, hemicellulosee, gums, pectinsdeg, aliginates and other polysaccharides.In herbivorous animals, intestinal microoganism breakdown these polysaccharides into acetate, propionate and butyrate.These polysaccharides contain 13-glycosidic linkages.Therefore, they cannot be digested by a-amylase present in human saliva and pancreatic juice because a-amylase breaks a-glycosidic bond (especially 1-4 a linkage).So, dietary fibers are not digested or hydrolyzed but are fermented by colonic bacteria except for lignin, which is neither digested nor fermented by intestinal microorganismsdeg.Dietary fibre absorbes water in the intestine, swells, increase bulk of stool by increasing water content of faeces and soften it, decreases transit time by facilitating colonic tansit."The presence of fibre shoens the transit timese and increases the stool bulk".Dietary fibre is of two types : -Soluble fibree : - These are pectin, aliginates, and gums. These absorb upto 15 times its weight in water as it moves through GIT, producing softer stools. Its good sources are oat, flaxseeds, peas, beans, apple, citrus fruits, carrots, bareley and psyllium.Insoluble fibredeg : - These are cellulose, hemicellulose and lignin. These promote movement of material through digestive system and increases stool bulk. Its good sources are wheat flour, wheat bran, nuts and vegetables.