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: Medicine
[{'content': 'What is the definitive method of diagnosing pulmonary embolism ? \nSelect and explain. \nA. Ventilation perfusion imaging, B. Positron Emission Tomography, C. High Resolution CT, D. Pulmonary angiography', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]