This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Regional anaesthesia, Subject name: Anaesthesia
[{'content': 'Onset of post spinal headache is usually at___ hours after spinal anesthesia \nSelect and explain. \nA. 0-6, B. 12-Jun, C. Dec-72, D. 72-96', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Post spinal headache or post dural puncture headache has onset usually on second or third day post procedure. It is an occipital type of headache, aggravated on sitting and relieved in recumbent position', 'role': 'assistant'}]