This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Physiology
[{'content': 'O2 release to tissue is affected by all except \nSelect and explain. \nA. 2,3-DPG, B. pH, C. Bicarbonate, D. Globin chain', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans: c (Bicarbonate) Ref: Ganong 22nd ed/p.667O2 release to tissue depends on oxygen dissociation curve.Shift of oxygen dissociation curve depends upon 2,3 - DPG pH and globin chain.', 'role': 'assistant'}]