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': 'Ostearthritis commonly involves -a) Proximal IP jointb) Distal IP jointc) Ist carpometacarpal jointd) Wrist jointe) Distal radio - ulnar joint \nSelect and explain. \nA. abc, B. bc, C. acd, D. bcd', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Joint involvement in OA\n\nCommon joints : Knee, Hip, Spine (cervical, lumbosacral), Hand (PIP, DIP, first carpometacarpal), first tarso-metatarsal.\nUncommon joint : Shoulder\nSpared : Wrist, elbow, ankle, metacarpophalangeal.', 'role': 'assistant'}]