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: Medicine
[{'content': 'Bart hemoglobin is a tetramer of \nSelect and explain. \nA. γ globin, B. β globin, C. α globin, D. δ globin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Bart Hb is a tetramer of excess\xa0γ globin.', 'role': 'assistant'}]