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 associated with hypertrophy of: \nSelect and explain. \nA. Filiform papillae., B. Fungiform papillae., C. Circumvallate papillae., D. Foliate papillae.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hairy Tongue:\n\nCharacterized by hypertrophy of Filiform papillae with lack of normal desquamation\nDorsal surface of tongue gives thick matted appearance\nExtrinsic stains may color the tongue from, white to brown to black.', 'role': 'assistant'}]