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: Physiology
[{'content': 'Pressure on carotid sinus causes \nSelect and explain. \nA. Hyperapnea, B. Tachycardia, C. Reflex bradycardia, D. Dyspnea', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]