Drone exam · Ground-risk mitigation Safety When do cones count as an effective ground control? Select one answer A When they actually keep people out or work as part of a system that does. B Whenever four cones are present. C Only when they are orange. D Even when people ignore them. Check answer Correct answer: A. When they actually keep people out or work as part of a system that does. Effectiveness is measured by behavior and control, not by the presence of equipment.