What should you do when a volunteer brings a horse into the arena before a lesson?

Having a volunteer walk the horse around the arena before a lesson serves multiple essential purposes. This action helps to ensure that the horse is calm and acclimated to the environment, which is particularly important in a therapeutic riding setting where both the horse and riders may be sensitive to their surroundings. Walking the horse allows for a gradual introduction to the arena ambiance, including sounds, smells, and other visual stimuli, which can reduce anxiety for the horse.

Additionally, this approach provides an opportunity to observe the horse's demeanor and physical condition before the lesson begins. It allows instructors and volunteers to check for any signs of distress or discomfort, ensuring that the horse is fit for the session ahead. Moreover, leading the horse also gives volunteers a chance to establish rapport and control over the horse, which is crucial for the safety of all participants.

The other options do not effectively prepare the horse or the environment for a safe and successful lesson. Allowing the horse to roam freely could lead to uncontrolled movements and create a potentially hazardous situation in the arena. Immediately mounting and riding the horse without proper groundwork can lead to safety issues and does not allow for an assessment of the horse's readiness. Feeding the horse a treat, while potentially well-intentioned, can disrupt focus and create risks