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': 'At the level of Arch of aoa, the relationship of left vagus nerve and left phrenic nerve? \nSelect and explain. \nA. Phrenic nerve anterior, vagus nerve posterior, B. Phrenic nerve posterior, vagus nerve anterior, C. Both in same plane anteroposteriorly, D. Variable in relationship', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Phrenic nerve anterior, vagus nerve posterior', 'role': 'assistant'}]