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: Anatomy
[{'content': 'Normal pressure of CSF is \nSelect and explain. \nA. 10 - 60 mm of water, B. 20-70 mm of water, C. 60 - 80 mm of water, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cerebrospinal fluid (CSF)\n\nCSF is present in the ventricular system of the brain and in the subarachnoid space around the brain and spinal cord.\nThe CSF is mainly formed by the choroid plexuses of lateral ventricles and lesser amounts by the choroid plexus of 3rd and 4th ventricles.\nThe total quantity of CSF is about 150ml. It is formed at the rate of about 200 ml / hr or 5000 ml / day. The normal pressure is 10-60 mm of H2O.', 'role': 'assistant'}]