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
What is the surgical indication for performing the Hunterian Ligation operation? 
Select and explain. 
A. Aneurysm, B. Varicose veins, C. A V fistulas, D. Acute aerial ischemia Ans
A: Aneurysm
Answer: A: Aneurysm 
Explanation: Hunterian ligation (parent vessel occlusion) is generally only considered if occlusion of the aneurysm neck is dangerous or impossible. It reduces flow past the aneurysm, often reducing the size of the lesion and even occasionally causing spontaneous thrombosis. Ref: Neurosurgery: Principles and Practice By Anne J. Moore, David W. Newell, 2005, Page 323.