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 value of magnesium ? \nSelect and explain. \nA. 1.5 mEq/L, B. 5 mEq/L, C. 25 mEq/L, D. 50 mEq/L', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 1.5 mEq/L", 'role': 'assistant'}]