This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal system, Subject name: Radiology
[{'content': "Bamboo spine is seen in - \nSelect and explain. \nA. Ankylosing spondylitis, B. RA, C. Paget's disease, D. Fibrous dysplasia", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Radiological features of Ankylosis spondylitis are : Sacroiliitis Enthesopathy Romanus lesions Bamboo spine Rugger Jersy spine Interveebral disc calcification Dagger sign Trolley track sign Squarring of veebrae.', 'role': 'assistant'}]