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': 'In the presence of vasopressin the greatest fraction of filtered water is reabsorbed in which pa of the nephron? \nSelect and explain. \nA. Proximal tubule, B. Distal tubule, C. Loope of Henle, D. Collecting duct', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The proximal tubule is responsible for reabsorbing ~60% of filtered water irrespective of the presence or abscence of vassopressin. Ref: Harrisons principles of internal medicine, 18th edition, chapter: 277.', 'role': 'assistant'}]