Which action involves a horse being led at a distance from the handler?

Longeing is the action where a horse is led at a distance from the handler, typically in a circular motion. During this process, the horse is attached to a long line or lunge line and is guided around the handler, allowing for controlled exercise and the opportunity to evaluate the horse's movement and behavior. Longeing enables the trainer or handler to work the horse without riding, helping to develop the horse's balance, rhythm, and responsiveness to commands. This method is particularly useful for training young horses or for assessing their readiness for more advanced training.

The other options represent different actions related to horses but do not involve the same distance from the handler. Sacking out refers to the process of desensitizing a horse to various stimuli, which is typically done while the horse is close to the handler. Riding involves direct contact with the horse as the rider is mounted on its back. Training can encompass a variety of techniques, but it usually involves the handler being in close proximity to the horse.