What is the earliest and best method to recognize a trailer skid?

Answer: C — Seeing it in your mirrors

Recognizing a trailer skid early is crucial for maintaining control of the vehicle combination. Seeing the skid in your mirrors is the most effective method because it allows you to visually confirm that the trailer is losing traction. This visual observation provides immediate feedback about the trailer's movement and position relative to the vehicle, enabling quick and appropriate corrective action. Mirrors offer a direct line of sight to the behavior of the trailer, which helps you assess its stability. While hearing a noise from the trailer or feeling a vibration in the tractor might indicate an issue, these signs tend to be less immediate and could create a delay in your reaction. Noticing a drop in speed can be a consequence of the skid but is not as direct or reliable a method for early recognition as viewing it in your mirrors. Therefore, visual awareness through your mirrors stands out as the best method to address a potential trailer skid promptly.