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: Radiology
[{'content': 'Drug used as pharmacological stress in stress echo \nSelect and explain. \nA. Dopamine, B. Dobutamine, C. Isoprenaline, D. Nitroprusside', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pharmacological stress : Dobutamine.\nPhysiological stress : Ttreadmill or bicycle exercise.', 'role': 'assistant'}]