What is one of the primary purposes of runway centerline lights?

The primary purpose of runway centerline lights is to provide guidance for landing approaches. These lights are positioned along the centerline of the runway and are designed to help pilots align their approach with the runway, particularly during low visibility conditions, such as night operations or inclement weather. The lights enhance the pilot's ability to identify the center of the runway and facilitate a more precise landing, contributing to overall flight safety.

In this context, while other options may seem plausible, they do not accurately represent the main function of runway centerline lights. For example, runway occupancy is indicated by different light systems, such as runway status lights. Taxing instructions are typically conveyed through signage and ground markings rather than runway lighting. As for the idea of decoration, runway lights serve a functional purpose and are not intended for aesthetic enhancement. This makes the provided answer clearly aligned with the operational goals of aviation safety and efficiency.