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: Pharmacology
[{'content': 'A hypertensive patient has heart rate of 50 beats/min and taking tablet atenolol 200 mg/day in divided doses. After anaesthesia, heart rate further fell down to 40 beats/min. What will be the appropriate treatment to improve heart rate: \nSelect and explain. \nA. IV adrenaline, B. IV atropine, C. IV isoprenaline, D. Dobutamine infusion intravenously', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]