This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Osteology, Subject name: Anatomy
[{'content': 'Metacarpophalangeal joint is \nSelect and explain. \nA. Condylar, B. Ellipsoid, C. Saddle, D. Hinge', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ellipsoid(functionally) / condylar joints(structurally): 1. Wrist (radio-carpal joints) 2. Knuckle (metacarpophalangeal joint) 3. Atlanto - occipital joint Ellipsoid > condylar joints', 'role': 'assistant'}]