This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Radiology
[{'content': 'A patient presents with a solitary pulmonary nodule (SPN) on X-ray. The best investigation to come to a diagnosis would be - \nSelect and explain. \nA. MRI, B. CT scan, C. USG, D. Image guided biopsy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: CT scan is the idol method to come to diagnosis of SPN', 'role': 'assistant'}]