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': 'A patient suffering from morning stiffness >1 hour, presents with the following abnormality in the X-ray. What can be the most possible diagnosis: \nSelect and explain. \nA. Psoriatic arthritis, B. Rheumatoid arthritis, C. Osteoarthritis, D. Relapsing polychondritis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B Rheumatoid arthritisClassic Swan neck deformityQ (DIP joint flexion and PIP joint extension) with marked changes at the radiocarpal joint.', 'role': 'assistant'}]