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: Orthopaedics
[{'content': 'Earliest radiological change in RA - \nSelect and explain. \nA. Decreased joint space, B. Articular erosion, C. Periarticular osteopenia, D. Subchondral cyst', 'role': 'user'}, {'content': 'Answer: C \nExplanation: "The radiographic findings in early RA are normal or soft tissue swelling and periarticular osteopenia".\xa0___\xa0Mayo clinic', 'role': 'assistant'}]