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': 'Beta agonist which is used for stopping premature labor is: \nSelect and explain. \nA. Carvedilol, B. Terbutaline, C. Pindolol, D. Nadolol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]