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 an open eruption technique for the exposure of impacted maxillary canine: \nSelect and explain. \nA. Window technique, B. Full flap technique, C. Apically positioned flap, D. Tunnel approach', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]