This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Aortic Imaging, Subject name: Radiology
Best investigation for diagnosing abdominal aortic aneurysm is? 
Select and explain. 
A. USG, B. CT angiography, C. Classical radiography, D. Non contrast CT scan
B: CT angiography
Answer: B: CT angiography 
Explanation: Ans. (b) CT angiographyRef. Interventional cardiology by sinha, p 134, Harrison's 17/e, chapter 242