This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Malabsorbtion Syndrome, Subject name: Medicine
Xylose absorption test is used to assess: 
Select and explain. 
A. Insulinoma, B. Atypical carcinoid, C. ZES, D. Monosaccharide absorption
D: Monosaccharide absorption
Answer: D: Monosaccharide absorption 
Explanation: Condition Investigation of choice Insulinoma 72 hour prolonged fasting Atypical carcinoid 5 HTP ( hydroxyl tryptophan) ZES Secretin study Monosaccharide malabsorbtion D xylose absorption test