This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous system, Subject name: Physiology
[{'content': 'Pain sensitive intracranial structure is \nSelect and explain. \nA. Piamater, B. Pial vessels, C. Duramater, D. Brain matter', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Pain-Sensitive Structures. Headache is caused by traction, displacement, inflammation, vascular spasm, or distention of the pain-sensitive structures in the head or neck. Isolated involvement of the bony skull, most of the dura, or most regions of brain parenchyma does not produce pain. Ref: guyton and hall textbook of medical physiology 12 edition page number: 687,688,689', 'role': 'assistant'}]