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': 'DOC of pustular psoriasis \nSelect and explain. \nA. PUVA, B. Methotrexate, C. Steroid, D. Cyclophosphamide', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Methotrexate', 'role': 'assistant'}]