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
A patient has a frequent tendency of migraine attacks. Which of the following drug should be given as prophylaxis? 
Select and explain. 
A. Propranolol, B. Pindolol, C. Ergotamine, D. All of the above
A: Propranolol
Answer: A: Propranolol 
Explanation: Prophylaxis of migraine is required if the attacks are frequent (>2-3 per month). The drugs useful for prophylaxis are: 

Propranolol is the most commonly used drug for prophylaxis of migraine attacks.
Timolol, atenolol, metoprolol and nadolol can also be used but the drugs with ISA (e.g. pindolol) are ineffective.