This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal physiology, Subject name: Physiology
[{'content': 'The site of action of vasopressin is \nSelect and explain. \nA. Ascending limb of loop of Henle, B. Descending limb of loop of Henle, C. Distal tubule, D. Proximal tubule', 'role': 'user'}, {'content': "Answer: C \nExplanation: Vasopressin (ADH) Increasing the water permeability of distal tubule and collecting duct cells in the kidney, thus allowing water reabsorption and excretion of more concentrated urine. Ref: Ganong's Review of Medical Physiology; 24th edition; page no: 698", 'role': 'assistant'}]