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': "Game Keeper's thumb is : \nSelect and explain. \nA. Ulnar collateral ligament injury of MCP Joint, B. Radial collateral ligament injury of MCP joint, C. Radial collateral ligament injury of CMC joint, D. Ulnar collateral ligament injury of CMC joint", 'role': 'user'}, {'content': "Answer: A \nExplanation: Injury to the ulnar collateral ligament of the thumb metacarpophalangeal joint is commonly referred to as gamekeeper's thumb or skier's thumb.\nInjury occurs by fall on hand with forceful radial and palmar adduction of thumb as seen in skiers.\nIt is the most common injury of MCP joint.", 'role': 'assistant'}]