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: Surgery
[{'content': 'Which of the following does not cause vomiting in a post-operative patient: \nSelect and explain. \nA. Ingested blood, B. N2O, C. Acetaminophen, D. Opioids', 'role': 'user'}, {'content': 'Answer: C \nExplanation: It is an analgesic and antipyretic drug which is used for the management of postoperative pain in a surgical patient. By reducing the postoperative pain, it reduces the incidence of post-operative nausea and vomiting.', 'role': 'assistant'}]