Before beginning the filling operation for RV tanks, what must be turned off?

Turning off appliance pilots and electronic ignition systems is essential before beginning the filling operation for RV tanks to ensure safety. When LP-gas is being filled, there is an inherent risk of leaks or spills occurring during the process. If appliance pilots or electronic ignition systems are left on, they could ignite any escaping gas, leading to fire hazards or explosions. By ensuring these systems are turned off, you effectively minimize the risk of ignition during the refueling operation, thereby promoting a safer environment for both the person dispensing the gas and anyone nearby.

While other options may also seem relevant in a comprehensive safety protocol, they do not specifically address the immediate risks associated with the act of filling LP-gas tanks. Focusing on the potential ignition sources is critical in preventing accidents during this sensitive operation.