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
Hairy tongue is associated with hypertrophy of: 
Select and explain. 
A. Filiform papillae., B. Fungiform papillae., C. Circumvallate papillae., D. Foliate papillae.
A: Filiform papillae.
Answer: A: Filiform papillae. 
Explanation: Hairy Tongue:

Characterized by hypertrophy of Filiform papillae with lack of normal desquamation
Dorsal surface of tongue gives thick matted appearance
Extrinsic stains may color the tongue from, white to brown to black.