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': 'Defenitive test to diagnose pulmonary embolism \nSelect and explain. \nA. V/Q Scan, B. Chest X-ray, C. CT pulmo angrography, D. MRI', 'role': 'user'}, {'content': 'Answer: C \nExplanation: CTPA is defenitive test or gold standard test.', 'role': 'assistant'}]