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': 'All of the following factors influence Oxygen haemoglobin dissociation curve, except \nSelect and explain. \nA. Chloride ion conc., B. CO2 tension, C. Temperature, D. 2,3 DPG', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]