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: Surgery
All of the following are true about aortic aneurism except 
Select and explain. 
A. Saccular aneurism involves whole circumference, B. True aneurism involves all 3 layers, C. Atherosclerosis is the commonest cause, D. False aneurism is not covered by all 3 layers
A: Saccular aneurism involves whole circumference
Answer: A: Saccular aneurism involves whole circumference 
Explanation: None