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': 'Single tooth cross bite can be treated by: \nSelect and explain. \nA. Removable or fixed appliances, B. Expansion appliance, C. Extraoral elastic, D. Head gear', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]