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: Anatomy
[{'content': 'In rheumatoid ahritis which pa of spinal column is most commonly involved ? \nSelect and explain. \nA. Cervical veebra, B. Dorsal veebra, C. Lumbar veebra, D. Sacral veebra', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Upper cervical spine is involved in RA Refer Harrison 17the p 2083/maheswari 9th ed', 'role': 'assistant'}]