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: Medicine
A chromosomal anomaly associated with alzheimer's dementia is - 
Select and explain. 
A. Trisomy 18, B. Patau syndrome, C. Trisomy 21, D. Turners syndrome
C: Trisomy 21
Answer: C: Trisomy 21 
Explanation: None