Which of the following parts is located between the horse's knee and fetlock?

The correct answer is the cannon bone, as this bone is situated between the horse's knee (carpus) and the fetlock joint (metacarpophalangeal joint). The cannon bone serves as a significant support structure in the horse's leg, playing a crucial role in weight distribution and movement.

The hindquarters refer to the back part of the horse's body and do not specifically relate to the area between the knee and fetlock. The fetlock joint is a juncture rather than a bone, and the carpal bones are part of the knee area itself. Thus, identifying the cannon bone highlights its anatomical position and importance in the horse's leg structure.