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: Unknown
[{'content': 'The most common cause of Urinary Ascitis is: \nSelect and explain. \nA. Pelviureteral junction obstruction, B. Posterior urethral valves, C. Urethral structure, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Important points about posterior urethral valves:\n• Symmetrical folds of urothelium.\n• Common distal to verumontanum.\n• Occur in males only.\n• MC cause of urinary obstruction (Urinary Ascites) in male infant.\n• Cause obstruction to passage of urine and catheter.\n• Diagnosis is by VCUG and Endoscopy.', 'role': 'assistant'}]