The correct option is D Tendons / ligaments.
Sesamoid bones are small independent bones or bony nodules developed in a tendon where it passes over an angular structure. It is found in the hands and feet. These rounded masses which are embedded in certain tendons related to joint surfaces functions to modify pressure, to diminish friction, and occasionally to alter the direction of a muscle pull. The sesamoid bones are the focal areas of ossification within the tendons.