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
Meckel's diverticulum is a derivative of - 
Select and explain. 
A. Allantoic diverticulum, B. Vitellointestinal duct, C. Ventral mesogastrium, D. Ductus arteriosus
B: Vitellointestinal duct
Answer: B: Vitellointestinal duct 
Explanation: None