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
Knee is which type of joint: 
Select and explain. 
A. Synarthrosis, B. Symphysis, C. Amphiarthrosis, D. Diarthrosis
D: Diarthrosis
Answer: D: Diarthrosis 
Explanation: Synarthrosis are immovable joints and include the ﬁbrous joints.
Amphiarthrosis are slight mobile and include the cartilaginous joints.
Diarthrosis are freely mobile joints and include the synovial joints.