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': 'In patients with facial disproportion producing malocclusion \nSelect and explain. \nA. an osteotomy alone in the mandibular ramus can be used to close an anterior open bite., B. a sagittal split osteotomy commonly produces inferior dental nerve paraesthesia, C. an intra oral vertical sub sigmoid osteotomy is appropriate for treating mandibular retrognathia., D. following a down fracture of the maxilla at Le Fort I level the blood supply to the alveolus relies only on the integrity of the greater palatine artery', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]