What does a steady green light on the ground indicate?

A steady green light on the ground indicates that an aircraft is cleared to land. This signal is used by air traffic control to communicate to the pilot that it is safe to approach and land on the runway. The clarity of a steady green light ensures that the pilot understands the instruction and can safely complete the landing maneuver.

Understanding this signal is crucial for safe flight operations, as it helps pilots maintain awareness of their clearance status while approaching the airport. The other options represent different instructions or signals given in aviation, but none indicate a landing clearance like the steady green light does.