In terms of aviation safety, what must any obstruction in a water area of an airport comply with?

The focus on aviation safety emphasizes the need for clear communication and management of airspace and surrounding areas. Any obstruction in a water area of an airport is critical to ensuring safe aircraft operations. The requirement for such obstructions to be kept clear as directed by air traffic control ensures that they do not interfere with flight paths or emergency landings.

Air traffic control plays a crucial role in overseeing the safe movement of aircraft on the ground and in the airspace surrounding the airport. By directing that obstructions be kept clear, they are ensuring that pilots have an unobstructed view and pathway for take-offs, landings, and navigational maneuvers, which ultimately enhances safety.

Other options may involve aspects of airport management or safety but do not directly address the immediate need for clearance around obstructions in water areas as mandated by air traffic control, making the requirement to keep those areas clear essential for operational safety.