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': 'In rheumatoid arthritis, pathology starts in the - \nSelect and explain. \nA. Articular cartilage, B. Capsule, C. Synovium, D. Muscles', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Major target in RA is synovium (synovial membrane) of the joint where the pathology starts.\nInflammation starts in the synovium and later also causes cartilage damage and bone erosion with subsequent change in joint integrity.', 'role': 'assistant'}]