To ensure the fuel is available for starting the engine, which position should the fuel selector switch be set to?

The fuel selector switch should be set to "Both" to ensure that fuel is available for starting the engine. By selecting "Both," the engine can draw fuel from both tanks, optimizing fuel availability and ensuring that no matter which tank has a higher fuel level, the engine will receive the fuel it needs to start and run effectively.

This setting is particularly important to prevent potential fuel starvation during critical phases such as starting the engine, as it allows the pilot to utilize the total amount of fuel available in the aircraft's fuel system. Selecting either "Left Tank" or "Right Tank" would limit fuel availability to just one tank, which could lead to complications if that tank is low or empty. Setting the selector to "Off" would obviously not allow fuel to flow to the engine at all, making it impossible to start.