It's true :) Flexibility is the range of motion around a joint, and can refer to ligaments, tendons, muscles, bones, and joints. If a joint has good range of motion then it would be able to move in all planes and directions permitted to that joint.
It is a completely true statement that flexibility is the capacity to move a joint through its full range of motion. The correct option among the two options that are given in the question is the first option. I hope that this is the answer that you were looking for and the answer has come to your desired help.
