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': 'Investigation of choice for pulmonary embolism – \nSelect and explain. \nA. CT scan, B. Contrast CT, C. Ventilation - Perfusion scan, D. MRI', 'role': 'user'}, {'content': 'Answer: B \nExplanation: No option is absolutely correct.\nThe 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.\nAmongst the given options, lung V/Q scan is the best option as it is the 2nd choice of the investigation after MDCTA.', 'role': 'assistant'}]