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': 'Current therapeutic status of milrinone in CHF is: \nSelect and explain. \nA. First choice drug for a patient of mild CHF, B. As an add on drug to tide over the crisis in refractory CHF, C. Best drug for long-term maintenance therapy of CHF, D. Used only to suppress digitalis induced arrhythmias', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]