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': 'Regarding CSF all the following statements are true except \nSelect and explain. \nA. Its pH is less than blood, B. No neutrophils present normally, C. Formed by arachnoid villi, D. Persistent leakage can cause headache', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Formed by arachnoid villi', 'role': 'assistant'}]