This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal System, Subject name: Physiology
Which disaccharide is not broken down into GIT by enzymatic action: 
Select and explain. 
A. Lactulose, B. Lactose, C. Sucrose, D. Isomaltose
A: Lactulose
Answer: A: Lactulose 
Explanation: Lactulose is nonabsorbable carbohydrate