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
A patient notices a well demarcated area of depapillation on his tongue which has been there for as long as he can remember. The most probable diagnosis: 
Select and explain. 
A. Median rhomboid glossitis, B. Geographic tongue, C. Black hairy tongue, D. Moeller's glossitis
A: Median rhomboid glossitis
Answer: A: Median rhomboid glossitis 
Explanation: None