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
[{'content': "Ligamentum terea is formed after ': \nSelect and explain. \nA. Obliteration of the umbilical vein, B. Obliteration of the ductus venous, C. Obliteration of the ductus aeriosus, D. Obliteration of the hypogastric aery", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Obliteration of the umbilical vein', 'role': 'assistant'}]