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
Metacarpophalangeal joint is 
Select and explain. 
A. Condylar, B. Ellipsoid, C. Saddle, D. Hinge
B: Ellipsoid
Answer: B: Ellipsoid 
Explanation: Ellipsoid(functionally) / condylar joints(structurally): 1. Wrist (radio-carpal joints) 2. Knuckle (metacarpophalangeal joint) 3. Atlanto - occipital joint Ellipsoid > condylar joints