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
Which of the following diagnostic techniques is most specific for pulmonary embolism? 
Select and explain. 
A. Pulmonary angiography, B. Ventilation lung scanning, C. Perfusion lung scanning, D. Arterial blood gas analysis
A: Pulmonary angiography
Answer: A: Pulmonary angiography 
Explanation: None