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': 'Hemoglobin does not bind with: \nSelect and explain. \nA. Oxygen, B. Carbon dioxide, C. Carbon monoxide, D. HCN', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Hemoglobin Combines Reversibly With Oxygen.\nCarbon monoxide (CO) combines with hemoglobin at the same point on the hemoglobin molecule as does O2 ; it can therefore\xa0 displace\xa0 O2\xa0 \xa0from\xa0 the\xa0 hemoglobin.\nCO2\xa0 \xa0reacts\xa0 directly\xa0 with\xa0 amine\xa0 radicals\xa0 of\xa0 the hemoglobin\xa0 molecule\xa0 to\xa0 form\xa0 the\xa0 compound\xa0 carbaminohemoglobin\xa0 (CO2 Hgb).\xa0\xa0\nThis\xa0 combination\xa0 of\xa0 CO2\xa0 \xa0and hemoglobin\xa0 is\xa0 a\xa0 reversible\xa0 reaction\xa0 that\xa0 occurs\xa0 with\xa0 a\xa0 loose\xa0 bond,\xa0 so\xa0 the\xa0 CO2\xa0 \xa0is\xa0 easily\xa0 released\xa0 into\xa0 the alveoli, where the PCO2\xa0 is lower than in the pulmonary capillaries.\n\nReference: : Guyton physiology pg no 532,535', 'role': 'assistant'}]