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': 'Structure passing along the aoa in the diaphragmatic opening : \nSelect and explain. \nA. Thoracic duct, B. Sympathetic duct, C. Greater splanchnic nerve, D. Lesser splanchnic nerve', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A. i.e. Thoracic duct', 'role': 'assistant'}]