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: Pathology
[{'content': 'Normal serum calcium level is \nSelect and explain. \nA. 5 to 7 mg%, B. 7 to 9 mg%, C. 9 to 11 mg%, D. 11 to 13 mg%', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]