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': 'Oral lesions on the tongue and other mucosal surfaces of the oral cavity is caused by the deficiency of: \nSelect and explain. \nA. Vit B1, B. Niacin, C. Vit C, D. Vit K', 'role': 'user'}, {'content': "Answer: B \nExplanation: A deficiency of niacin leads to the classic symptoms of pellagra in human beings.\nClinical Features of Pellagra:\n\nThe mucous membrane lesions affecting the tongue, oral cavity\xa0and vagina are usually the earliest lesions diagnostic of the disease.\nOther lesions common in pellagra are the typical dermal lesions of bilaterally symmetric, sharply outlined, roughened, keratotic areas. (The word ‘pellagra’ means rough skin).\xa0\nMental symptoms and weight loss also occur.\n\nRef: Shafer's textbook of oral pathology 7th edition page 646", 'role': 'assistant'}]