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: Surgery
[{'content': 'Primary rotation force is applied for the extraction of: \nSelect and explain. \nA. Max. central incisor + Mandibular 2nd premolar., B. Max. central incisor + Mandibular central incisor., C. Max. premolars., D. All of the above.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]