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: Forensic Medicine
[{'content': "Following is used to document tear of hymen in a victim of rape: AI 12; NEET 15 \nSelect and explain. \nA. Vaginal speculum, B. Glaister-keen rod, C. Cylinder rod, D. Hegar's rod", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Glaister-keen rod', 'role': 'assistant'}]