This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics, Subject name: Pathology
Edwards syndrome is due to:(1986) 
Select and explain. 
A. Trisomy 21, B. Trisomy 18, C. 18 p, D. Trisomy 13
B: Trisomy 18
Answer: B: Trisomy 18 
Explanation: Ans: b (Trisomy 18)Ref: Robbin's Patho, 7thed, p. 177 & 6thed, p. 172