This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Water reabsorption in renal tubules varies at different levels. The maximum reabsorption is at: \nSelect and explain. \nA. PCT, B. Collecting duct, C. Descending Loop of Henle, D. Ascending limb of Henle', 'role': 'user'}, {'content': "Answer: A \nExplanation: Sites of water reabsorption in the kidney: Proximal tubule (65% of the filtered water) Descending thin limb of Henle's loop (10%) Collecting-duct system (where the fractional reabsorption is the most variable) Ref: Eaton D.C., Pooler J.P. (2009). Chapter 6. Basic Renal Processes for Sodium, Chloride, and Water. In D.C. Eaton, J.P. Pooler (Eds), Vander's Renal Physiology, 7e.", 'role': 'assistant'}]