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': 'Thiazide diuretic used when GFR<30 ml/min? \nSelect and explain. \nA. Metolazone, B. Benzthiazidc, C. Chlohiazide, D. Hydrofulthiazide', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Metolazone o Metolazone is the only thiazide which is effective in severe renal failure.", 'role': 'assistant'}]