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
[{'content': 'Ligament teres is a remnant of ? \nSelect and explain. \nA. Ductus aeriosus, B. Umbilical aery, C. Umbilical vein, D. Ductus venosus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Umbilical vein', 'role': 'assistant'}]