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 patient has a frequent tendency of migraine attacks. Which of the following drug should be given as prophylaxis? \nSelect and explain. \nA. Propranolol, B. Pindolol, C. Ergotamine, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Prophylaxis of migraine is required if the attacks are frequent (>2-3 per month). The\xa0drugs useful for prophylaxis are:\xa0\n\nPropranolol is the most commonly used drug for prophylaxis of migraine\xa0attacks.\nTimolol, atenolol, metoprolol and nadolol can also be used but the drugs with ISA (e.g. pindolol) are ineffective.', 'role': 'assistant'}]