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
Absence of fungiform and circumvallate papillae seen in: 
Select and explain. 
A. Familial dysautonomia., B. Iron deficiency anemia., C. Scarlet fever., D. Riboflavin deficiency.
A: Familial dysautonomia.
Answer: A: Familial dysautonomia. 
Explanation: None