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': 'The best method for estimation of hemoglobin concentration in blood: \nSelect and explain. \nA. Acid hematin method, B. Alkali hematin method, C. Cyanmethemoglobin method, D. Any of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]