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: Dental
[{'content': 'Psoralen–A is used in the treatment of – \nSelect and explain. \nA. Pemphigus, B. Vitiligo, C. Pityriasis alba, D. Icthyosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]