The connective tissue that connects a muscle to a bone is called a tendon. A tendon is a tough and flexible band of fibrous tissue that is primarily made up of collagen fibers. Its main function is to transmit the force generated by the muscle to the bone, allowing movement of the skeletal system.

Option 1: Cartilage is a different type of connective tissue that provides support and cushioning between bones. It is not directly involved in connecting muscles to bones.

Option 2: Ligaments are also a type of connective tissue, but their function is to connect bones to other bones, providing stability to joints. They are not specifically involved in connecting muscles to bones.

Option 4: Interstitial fluid is the fluid that surrounds and bathes the cells in the body. It does not play a direct role in connecting muscles to bones.

In conclusion, the correct answer is option 3: Tendon. It is the connective tissue responsible for connecting a muscle to a bone and facilitating movement.