How far away from a helicopter landing zone should all vehicles, animals, and unauthorized persons remain?

The correct distance that vehicles, animals, and unauthorized persons should remain away from a helicopter landing zone is 150 to 200 yards. This distance is important for ensuring safety during helicopter operations. Helicopters create strong downwash and can kick up debris, which can be hazardous to those nearby. Maintaining a buffer zone helps to prevent accidents and injuries.

Furthermore, this specified distance allows for safe maneuvering and landing, as well as the ability for the flight crew to have adequate visibility and operational space. In a search and rescue situation, this safety margin is vital, enabling the helicopter to approach the landing zone without risk of colliding with obstacles or people who might be too close to the area.

Other choices suggest distances that either exceed or are less than the recommended safe range, potentially compromising the safety of personnel and operations around the landing zone.