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 child with Down's syndrome has Moon facies, retarded mentally and which of the facial characteristics: 
Select and explain. 
A. Maxillary prognathism, B. Mandibular retrognathia, C. Mandibular prognathism, D. Maxillary hypoplasia
D: Maxillary hypoplasia
Answer: D: Maxillary hypoplasia 
Explanation: None