This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Pediatrics
A 6-year-old child is brought by his new foster mother who was concerned that when she brushed his teeth last night she noticed that his tongue was red in certain distinct patterns. He has otherwise not been ill: The most likely diagnosis he has is: 
Select and explain. 
A. Kawasaki disease, B. Pyogenic granuloma of the tongue, C. Geographic tongue, D. Hairy tongue
C: Geographic tongue
Answer: C: Geographic tongue 
Explanation: Ans. C. Geographic tongueGeographic tongue can have a changing appearance, hence its alternative description, erythema migrans. It involves atrophy of the filiform papillae, usually on the dorsum of the tongue. It is harmless and common. Hairy tongue is usually dark colored; it is caused by excess keratin and hypertrophy and elongation of the filiform papillae. Usually these patients are asymptomatic. Patients with Kawasaki traditionally have "strawberry tongue," where the tongue is red and slightly swollen and the papillae appear white as a contrast. These patients are generally quite ill, with high fevers for several days and other symptoms. Pyogenic granulomas can grow on the tongue, although they would be more commonly found on the gingiva, as they are caused by the body's reaction to irritation. It is a painless mass that can be red, blue, or purple