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': "In the Begg's fixed appliance, a bracket having: \nSelect and explain. \nA. Horizontal slot is used with round wire, B. Horizontal slot is used with rectangular wire, C. Vertical slot is used with round wire, D. Vertical slot is used with rectangular wire", 'role': 'user'}, {'content': 'Answer: C \nExplanation: The bracket used in Begg fixed appliance mechanotherapy is modified ribbon arch bracket, with vertical slot and opening of this bracket is in occlusal/incisal direction. Dr. Begg proposed use of special type of round wire called Australian wire in his technique.', 'role': 'assistant'}]