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': 'A double aoic arch is due to persistent: \nSelect and explain. \nA. Right 4th arch, B. Right 6th arch, C. Left 4th arch, D. Left 6th arch', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Right 4th arch', 'role': 'assistant'}]