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: Dental
[{'content': 'Vomiting during impression making procedures may be \nprevented by: \nSelect and explain. \nA. Sedating the patient, B. Injecting local anesthetic, C. Asking patient to come empty stomach, D. Change the impression material', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]