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: Anatomy
[{'content': 'First carpometacarpal joint is a - \nSelect and explain. \nA. Hinge joint, B. Saddle joint, C. Elipsid joint, D. Synol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Saddle', 'role': 'assistant'}]