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: Pharmacology
[{'content': 'Opioid induced constipation is treated by \nSelect and explain. \nA. Loperamide, B. Biperiden, C. Alvimopan, D. Naltrexone', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Alvimopan, Naloxegal & Methyl naltrexone are peripherally acting opioid antagonists used to treat opioid induced constipation & paralytic ileus.', 'role': 'assistant'}]