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: Surgery
True about omphalocele is all, EXCEPT: 
Select and explain. 
A. Umbilical cord inses into the sac, B. Incidence of approximately 1 in 5000 live bihs, C. Abdominal wall defect measures >=4 cm in diameter, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: Omphalocele refers to a congenital defect of the abdominal wall in which the bowel and solid viscera are covered by peritoneum and amniotic membrane. The umbilical cord inses into the sac. The abdominal wall defect measures >=4 cm in diameter. Omphalocele has an incidence of approximately 1 in 5000 live bihs. Ref: Schwaz's principle of surgery 9th edition, chapter 39.