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: Radiology
[{'content': 'Best method to diagnose pulmonary embolism: \nSelect and explain. \nA. Pulmonary angiography, B. Scintillation perfusion scan, C. CT scan, D. X-ray chest', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Pulmonary angiography', 'role': 'assistant'}]