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': 'Hairy tongue is characterized by \nSelect and explain. \nA. Hypertrophy of fungiform papillae, B. Hypertrophy of foliate papillae, C. Hypertrophy of filiform papillae, D. Hypertrophy of circumvallate papillae.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]