When should the Load Team receive clearance to approach a C-17?

The correct choice highlights the importance of operational safety and communication in air freight operations involving C-17 aircraft. Clearance for the Load Team to approach the aircraft in low-speed ground idle or reverse thrust indicates that while the aircraft's engines are still running, they are at a reduced power setting that minimizes the risk of wake turbulence or jet blast that could endanger personnel nearby. Ensuring the aircraft is at a controlled power setting allows for the Load Team to maneuver around it safely while still benefiting from the aircraft's readiness to perform its mission.

The other options, while addressing safety concerns, do not capture the necessary balance between ensuring the aircraft's engines are under control and allowing the Load Team to efficiently begin their operations. Receiving clearance only when the engines are off may delay essential loading processes that need to occur while the aircraft is actively preparing for its next mission. Being stationary is less relevant, as an aircraft can be stationary yet still pose hazards if the engines are at a higher throttle setting. Conducting a safety briefing is an important practice, but it doesn't provide the immediate operational clearance needed for the Load Team to approach the aircraft effectively.