The correct option is D Synovial joints
A synovial joint is a connection between two bones consisting of a cartilage lined cavity filled with fluid. Synovial joints are capable of the greatest movement. Knees, elbows and shoulders are examples of synovial joints. Since they allow for free movement, synovial joints are classified as diarthrosis. They allow for many types of movement including gliding, angular, rotational etc. So, the correct answer is 'Synovial joints'.