This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
[{'content': 'Proximal & distal renal tubular acidosis is differentiated by all except- \nSelect and explain. \nA. Stones in kidney, B. Hypokalemia, C. Daily acid secretion, D. Presence of Fanconi syndrome', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Refer to the previous question no. 20(explanation was given there )', 'role': 'assistant'}]