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': 'Which of the following is not true of a fixed appliance \nSelect and explain. \nA. Economical, B. Rotation and extrusion movements are possible, C. Patient co-operation is not required, D. Tipping and bodily movement are possible', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]