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
[{'content': 'Which of the following is true about varicocele except? \nSelect and explain. \nA. Incompetent valves of testicular vein are responsible for varicocele, B. 90% are on the left side, C. Asymptomatic cases require surgery, D. Femoral catheterization with spermatic vein ablation is done in recurrence', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]