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: Anatomy
[{'content': 'Location of carotid sinus is: \nSelect and explain. \nA. At the termination of CCA, B. Behind the bifurcation of CCA, C. At the beginning of ICA, D. Both 1 and 3', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Carotid sinus:\n\nIt is a fusiform dilatation at the terminal end of common carotid artery or at the beginning of internal carotid artery.\xa0\nIt has rich innervation from glossopharyngeal, vagus, and sympathetic nerves.\xa0\nThe carotid sinus acts as a baroreceptor (pressure receptor) and regulates the blood pressure in the cerebral arteries.\n\nKey Concept:\nCarotid sinus is a fusiform dilatation at the terminal end of common carotid artery or at the beginning of internal carotid artery.', 'role': 'assistant'}]