The answer is letter B.
Flexibility is a very important component in exercise. Without flexibility the range of motion of joints will be limited which will result to serious injuries. Often it is the most overlooked part of a training program but if athletes knew of the benefits it could bring they will surely be performing this in their programs. Flexibility can be developed through a wide variety of active and passive stretches. It improves performance because joints can easily move and are not restricted to perform the necessary muscle contractions needed for a particular activity.