What does the fuel system need to ensure for each powerplant?

The fuel system must ensure that it provides the necessary fuel and operational functions under common conditions for each powerplant to function efficiently and reliably. This means that the system should be capable of supplying the correct amount of fuel consistently, regardless of the operational scenario the engine might face, such as changes in altitude, temperature, or engine power output demands.

By delivering the appropriate fuel mixture and maintaining the necessary fuel pressure and flow, the fuel system helps to maximize engine performance while ensuring safe operation. This includes accommodating various phases of flight, such as takeoff, cruising, and landing, where power requirements can fluctuate.

Other options suggest scenarios that are not viable for safe aircraft operation. For example, suggesting that a powerplant can run without fuel or only operates effectively at maximum capacity would not only be incorrect but also unsafe. The fuel system must be versatile enough to handle different performance requirements, which is precisely why the correct answer emphasizes the importance of providing essential fuel and operational functions under typical conditions.