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 false about vaginal hydrocele \nSelect and explain. \nA. Transillumination is always positive, B. It can occur secondary to epididymo-orchitis, C. Patent processus vaginalis is a risk factor, D. Most common cause is idiopathic', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Not all hydrocele are transillumination positive.\nSecondary hydrocoele have turbid fluid collection.', 'role': 'assistant'}]