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
Ligamentum teres is a remnant of which of the following embryologic structure? 
Select and explain. 
A. Umbilical aery, B. Ductus venosus, C. Umbilical vein, D. Poal radicles
C: Umbilical vein
Answer: C: Umbilical vein 
Explanation: After bih left umbilical vein obliterates to form ligamentum teres. Initially umbilical veins pass on each side of the liver to drain into sinus venosus. Later proximal poion of both umbilical veins and remaining poion of right umbilical vein disappear. Left umbilical vein carry blood from placenta to the liver.Ductus venosus obliterates to form ligamentum venosum.Distal pa of umbilical aery obliterate to form medial umbilical ligament while its proximal poion forms the superior vesicle aery.Ref: Textbook of Human Embryology By Rani Kumar, Page 208