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: Pharmacology
[{'content': 'Site of action of anti diuretic hormone is : \nSelect and explain. \nA. Loop of Henle, B. Proximal tubule, C. Distal tubule, D. Cortical collecting duct', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]