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: Skin
[{'content': 'Treatment of nodulocystic acne ? \nSelect and explain. \nA. Erythromycin, B. Isoretinonine, C. Tetracycline, D. Steroids', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Isoretinonine", 'role': 'assistant'}]