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
Which of the following is an example of saddle joint 
Select and explain. 
A. Carpo-metacarpal joint of the thumb, B. Carpo-metacarpal joint of the thumb, C. Ankle joint, D. Knee joint
A: Carpo-metacarpal joint of the thumb
Answer: A: Carpo-metacarpal joint of the thumb 
Explanation: A i.e. Carpometacarpal joint of thumb