Human Sprinters Start a Race from a Crouched Position Because

Human sprinters start a race from a crouched position because

A) bone is strongest when loaded this way.
B) a flexed-limb posture reduces the energy cost of standing.
C) animals with a flexed-limb resting posture can produce rapid acceleration.
D) animals with highly flexed limbs have improved manoeuvrability.
E) a flexed limb is more easily moved than a rigid limb.