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': 'Standard urea clearance in an normal adult is? \nSelect and explain. \nA. 20 ml, B. 50 ml, C. 100 ml, D. 200 ml', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is'b'i.e., 50 mlStandard clearance of urea (Cs) and average normal value is 54", 'role': 'assistant'}]