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: Anatomy
Ligament teres is a remnant of ? 
Select and explain. 
A. Ductus aeriosus, B. Umbilical aery, C. Umbilical vein, D. Ductus venosus
C: Umbilical vein
Answer: C: Umbilical vein 
Explanation: Umbilical vein