This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
[{'content': 'Migraine is due to \nSelect and explain. \nA. Dilatation of cranial aeries, B. Constriction of cranial aeries, C. Coical spreading dissociation, D. Meningial inflammation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: K.D Tripathy essentials of medical pharmacology 7th edition . *Neurogenic theory consider it to be spreading depression of coical electrical activity followed by vascular phenomena.', 'role': 'assistant'}]