This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
[{'content': 'Which one of the following drugs is not a uterine relaxant? \nSelect and explain. \nA. Isoxsuprine, B. Dopamine, C. Salbutamol, D. Terbutaline', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Isoxsuprine, magnesium, ritodrine, salbutamol, and terbutaline to some extent, atosiban, calcium channel blockers could act as uterine relaxants or tocolytics Ref: KD Tripathi 8th ed', 'role': 'assistant'}]