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: ENT
[{'content': "Rose's position is extension at \nSelect and explain. \nA. C1 and C2 joint, B. Atlanto - occipital joint, C. C3 and C4, D. C5 and C6", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]