Which of the following is considered a natural riding aid?

The rider’s legs are considered a natural riding aid because they are a part of the rider's body and therefore promote a more harmonious connection between the horse and rider. Natural aids, which include the use of legs, hands, and weight, rely on the rider's body movements to communicate instructions to the horse. By using their legs, a rider can signal different cues such as moving forward, slowing down, or changing direction, all in a way that feels natural and fluid to the horse.

In contrast, items like a whip, spurs, and a martingale are classified as artificial aids. These tools are external accessories that a rider uses to assist with controlling the horse and enhancing communication but do not come from the rider's body directly. While they can be used effectively, they might not create the same level of understanding and responsiveness as the natural aids do, which foster a more intuitive interaction based on the rider's own physical cues.