This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Headache, Subject name: Medicine
The pain of migraine headache is due to - 
Select and explain. 
A. An idiopathic neuropathy, B. Reflex vasodilation of constricted vessels, C. Constriction of cranial arteries, D. Psychogenic overlay
B: Reflex vasodilation of constricted vessels
Answer: B: Reflex vasodilation of constricted vessels 
Explanation: Ans- B Reflex vasodilation of constricted vessels