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': '2 zeta and 2 gamma chains are present in which hemoglobin \nSelect and explain. \nA. Hb Portland, B. Hb gower I, C. Hb gower II, D. HbA2', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hb portland - 2 zeta & 2 gamma.\nHb Gower I - 2 zeta & 2 epsilon.\nHb gower II - 2 alpha & 2 epsilon.', 'role': 'assistant'}]