This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Congenital CNS malformations, Subject name: Pediatrics
Most specific congenital abnormality in a baby born to a diabetic woman is? 
Select and explain. 
A. Ventricular Septal defect, B. Sacral agenesis, C. Meningomyelocele, D. Transposition of great aeries
B: Sacral agenesis
Answer: B: Sacral agenesis 
Explanation: -Sacral agenesis or Caudal regression syndrome is the most specific congenital abnormality in a baby born to a diabetic woman.