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: Physiology
[{'content': 'Hemoglobin has: \nSelect and explain. \nA. Four polypeptide chains, 2α, 1β, 1γ chain, B. Four heme molecules and four polypeptide chains, C. Four heme molecules, 2α, and 2β chains, D. One heme and one globin molecule', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]