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': 'Magenta tongue is found in \nSelect and explain. \nA. Riboflavin deficiency, B. Scarlet fever, C. Familial dysautonomia, D. Median rhomboid glossitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]