This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arterial Disorders, Subject name: Surgery
A 66-year-old woman has a 5.5-cm infrarenal abdominal aortic aneurysm. What is the most common manifestation of such an aneurysm? 
Select and explain. 
A. Abdominal or back pain, B. Acute leak or rupture, C. Incidental finding on abdominal examination, D. Atheroembolism
C: Incidental finding on abdominal examination
Answer: C: Incidental finding on abdominal examination 
Explanation: Most patients are unaware of their abdominal aneurysm until it is incidentally discovered by their physician. The importance of careful deep palpation of the abdomen cannot be overemphasized. On occasion, these aneurysms may expand, causing abdominal or back pain, and may even leak or rupture, mimicking other acute intra-abdominal conditions. Signs and symptoms of acute ischemia in the lower extremities are rare and usually follow thrombosis or embolization from an abdominal aneurysm.