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: Medicine
Edward syndrome is: 
Select and explain. 
A. Trisomy 21, B. Trisomy 18, C. Trisomy 13, D. 5p deletion
B: Trisomy 18
Answer: B: Trisomy 18 
Explanation: Ans: b