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
[{'content': 'A patient presents with a cavitatory lesion in right upper lobe of Lung. The best investigation is \nSelect and explain. \nA. Branchoscopy, lavage and brushing, B. C. T. scan, C. X ray, D. FNAC', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]