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': 'Which of the following ion is absorption in proximal convoluted tubule? \nSelect and explain. \nA. Na+, B. Urea, C. K+, D. Mg+', 'role': 'user'}, {'content': "Answer: A \nExplanation: Maximum sodium reabsorption occours in PCT. Ref: Ganong's review of medical physiology; 24th edition; page no: 681", 'role': 'assistant'}]