What are the two main types of lights used for runway lighting?

The correct response identifies runway threshold lights and edge lights as the two main types of lighting used for runway lighting. Runway threshold lights are crucial as they indicate the beginning of the runway that is available for landing or takeoff. These lights help pilots in identifying the precise point where the runway starts, especially under low visibility conditions.

Edge lights are positioned along the sides of the runway and serve to delineate the runway's edges. They are typically white for runways and provide guidance to pilots as they approach and use the runway during operations.

The other choices mention various lights that are either not standard for runway-specific lighting or serve different purposes entirely. For instance, landing lights are primarily used on aircraft, not for illuminating runways. Wingbar lights do not pertain to runways but rather assist with visibility for certain types of aircraft configurations. Similarly, clearway and stopway lights refer to areas beyond the runway rather than the runway itself.