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': 'Which ni the lolioning o hen increased can cause a shift of the oxygen-hemoglobin dissociation curve to the left? \nSelect and explain. \nA. pH, B. Temperature, C. 2,3-BPG, D. pCO2', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a. pH', 'role': 'assistant'}]