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: Gynaecology & Obstetrics
Ligamentum teres is formed after 
Select and explain. 
A. Obliteration of the umbilical vein, B. Obliteration of the ductus venous, C. Obliteration of the ductus arteriosus, D. Obliteration of the hypogastric artery
A: Obliteration of the umbilical vein
Answer: A: Obliteration of the umbilical vein 
Explanation: Umbilical vein closure occurs shortly after closure of umbilical arteries and forms the ligamentum teres.