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: Anatomy
[{'content': 'The following structures are felt on per rectal examination except - \nSelect and explain. \nA. Bulb of penis, B. Ureter, C. Anorectal ring, D. Urogenital diaphragm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]