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: Pediatrics
Not true among the following is 
Select and explain. 
A. Most common cause of Down's syndrome is Maternal meiotic disjunction., B. Most Common inherited condition causing Intellectual disability in Fragile X Syndrome, C. The mandible in Down's child is smaller than usual, D. Isolated finding of simian crease in Down's in seen in almost 20% of Down's children.
D: Isolated finding of simian crease in Down's in seen in almost 20% of Down's children.
Answer: D: Isolated finding of simian crease in Down's in seen in almost 20% of Down's children. 
Explanation: Isolated finding of simian crease in Down's in seen in almost 1% of Down's children. So it is not a significant finding in a Down's child.