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: Surgery
Game Keeper's thumb is 
Select and explain. 
A. 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
A: Ulnar collateral ligament injury of MCP Joint
Answer: A: Ulnar collateral ligament injury of MCP Joint 
Explanation: A i.e. Ulnar collateral ligament injury of MCP Joint