This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'Chemical structure of hemoglobin is \nSelect and explain. \nA. Has 2 polypeptide chains with 4 heme, B. Has 4 polypeptide chains with 2 heme, C. Has 4 polypeptide chains with 4 heme, D. None of the above', 'role': 'user'}, {'content': "Answer: C \nExplanation: Hemoglobin is a protein with a molecular weight of 64,450.Hemoglobin is a globular molecule made up of four subunits . Each subunit contains a heme moiety conjugated to a polypeptide. Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No: 523", 'role': 'assistant'}]