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: Unknown
Abdominal aortic aneurysm is operated when the size is more than: 
Select and explain. 
A. 35 mm, B. 45 mm, C. 55 mm, D. 65 mm
C: 55 mm
Answer: C: 55 mm 
Explanation: Ref. Sabiston Textbook of Surgery. Pg. 1723
 
INDICATIONS FOR OPERATION
Asymptomatic –

Aneursym  >55mm in anteroposterior diameter.
Patient fit for surgery (expected mortality rate <5%)
Indications for endoluminal operation are the same as for open operation .

Symptomatic .

Aneursym of any size that is painful or tender
Aneursym of any size that is causing distal embolisation .
Indications are wider than for an asymptomatic lesion (expected mortality rate 5-20%)