This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Radiology
[{'content': 'Identity the structure in the given chest X-ray: \nSelect and explain. \nA. Left-Costophrenic angle, B. Left-Cardiophrenic angle, C. Right-Costophrenic angle, D. Right-Cardiophrenic angle', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b. Left-Cardiophrenic angle', 'role': 'assistant'}]