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
Best diagnostic aid for broncheitasis is: 
Select and explain. 
A. Bronchoscopy, B. X- Ray, C. Bronchography, D. CT Scan
D: CT Scan
Answer: D: CT Scan 
Explanation: D i.e. CT Scan