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': 'True regarding water absorption in tubules:September 2007 \nSelect and explain. \nA. Majority of facultative reabsorption occurs in proximal tubule, B. Bulk of water reabsorption occurs secondary to sodium absorption, C. 25% of water is reabsorbed irrespective of water balance, D. Obligatory reabsorption is ADH dependent', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: Bulk of water reabsorption occurs secondary to sodium absorptionWater reabsorption keeps pace with the sodium reabsorption in the proximal tubules and hence the concentration of sodium and total osmolarity remains the same.', 'role': 'assistant'}]