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
Investigation of choice for pulmonary embolism – 
Select and explain. 
A. CT scan, B. Contrast CT, C. Ventilation - Perfusion scan, D. MRI
B: Contrast CT
Answer: B: Contrast CT 
Explanation: No option is absolutely correct.
The pulmonary angiography has traditionally been considered as the gold standard test for pulmonary embolism. But, now a days CT contrast (MDCTA) is the investigation of choice.
Amongst the given options, lung V/Q scan is the best option as it is the 2nd choice of the investigation after MDCTA.