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: Biochemistry
[{'content': 'Normal serum calcium level is: \nSelect and explain. \nA. 4-6 mg/dl, B. 9-11 mg/dl, C. 19-21 mg/dl, D. 20-30 mg/dl', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Normal Blood Calcium level-9 : 11 mg/dl\nTotal Calcium level in the body\xa0is 1.5 kg.', 'role': 'assistant'}]