This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Spinal injuries, Subject name: Anatomy
[{'content': "Jafferson's fracture is the fracture of- \nSelect and explain. \nA. Odontoid, B. C1, C. C2, D. C3", 'role': 'user'}, {'content': "Answer: B \nExplanation: *Jefferson's fracture is the most common type of fracture of atlas(1) Ref: Apley's 9th/e p.813,814", 'role': 'assistant'}]