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
What is the definitive method of diagnosing pulmonary embolism ? 
Select and explain. 
A. Ventilation perfusion imaging, B. Positron Emission Tomography, C. High Resolution CT, D. Pulmonary angiography
D: Pulmonary angiography
Answer: D: Pulmonary angiography 
Explanation: None