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: Pathology
[{'content': 'Perleche is caused by \nSelect and explain. \nA. decreased interdental space, B. increased interdental space, C. Lack of Vit-C, D. Trauma to the corners of the mouth', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]