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': 'Spine of Henle is a: \nSelect and explain. \nA. Coical bone, B. Cancellous bone, C. Sclerotic bone, D. Long bone with Haversian system', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Spine of henle is a pa of mastoid bone. Mastoid is a spongy or cancellous bone, hence spine of henle is also cancellous.', 'role': 'assistant'}]