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': 'A 28-year-old male patient is brought to casualty in comatose state with pin-point pupils, reduced respira- tory rate and bradycardia. Most likely diagnosis: UPSC 09; CMC (Vellore) 14 \nSelect and explain. \nA. Tricyclic antidepressant poisoning, B. Opioid poisoning, C. Benzodiazepine poisoning, D. Organophosphorus poisoning', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Opioid poisoning', 'role': 'assistant'}]