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: Dental
All of the following about Down's syndrome are true except: 
Select and explain. 
A. PDL degeneration takes place, B. Tooth never exfoliates though there is advanced PDL loss, C. Deep periodontal pockets associated with a substantial plaque, D. Acute necrotizing lesions are a frequent finding
B: Tooth never exfoliates though there is advanced PDL loss
Answer: B: Tooth never exfoliates though there is advanced PDL loss 
Explanation: None