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': 'Best method for detecting minimal bronchiectasis is: \nSelect and explain. \nA. Bronchogram, B. CT scan, C. Radionuclide lung scan, D. Chest X-ray', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. CT scan', 'role': 'assistant'}]