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': 'Ligamentus aeriosus is a remnant of - \nSelect and explain. \nA. Ductus aeriosus, B. Ductus caroticus, C. Ductus venosus, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Ductus aeriosus', 'role': 'assistant'}]