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': 'Below …………………………. pressure, CSF absorption stops - \nSelect and explain. \nA. 60 mm CSF, B. 68 mm CSF, C. 80 mm CSF, D. 50 mm CSF', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Below a pressure of approximately 68 mmH2O, absorption stops.', 'role': 'assistant'}]