What does it mean to "trot a horse out"?

"Trotting a horse out" refers to the practice of evaluating its soundness by observing its movement at a trot. This action allows a handler or rider to assess how the horse is moving and to look for any signs of lameness or discomfort. Observing the horse in motion can reveal underlying issues that may not be apparent when the horse is standing still, such as asymmetries or irregular gait patterns. This assessment is crucial for ensuring that the horse is healthy and capable of participating in activities like riding, jumping, or competing.

Other choices relate to different aspects of horse management and training but do not specifically address the purpose of trotting a horse out. The focus on soundness evaluation is what makes this choice the correct answer.