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
Down's syndrome is associated with all except 
Select and explain. 
A. Retrognathia, B. Periodontal disease, C. Premature loss of deciduous teeth, D. Delayed eruption of deciduous teeth
A: Retrognathia
Answer: A: Retrognathia 
Explanation: None