This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Venous Disorders, Subject name: Surgery
[{'content': 'Contraindication for surgery in varicose veins:- \nSelect and explain. \nA. DVT, B. Multiple incompetent perforators, C. Ulcer at ankle, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: DVT is the contraindication for surgery in varicose veins as superficial veins are only channel for drainage of venous blood .', 'role': 'assistant'}]