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: Medicine
Absorptive function of the mucosa of intestine can be best assessed by - 
Select and explain. 
A. d-Xylose test, B. NET- PABA test, C. Stool fat estimation, D. Urobilin levels
A: d-Xylose test
Answer: A: d-Xylose test 
Explanation: D-xylose absorption test is a medical test performed to diagnose conditions that present with malabsorption of the proximal small intestine due to defects in the integrity of the gastrointestinal mucosa. D-xylose is a monosaccharide, or simple sugar, that does not require enzymes for digestion prior to absorption Ref Davidson edition23rd pg809