From which pump is the engine-driven high-pressure fuel pump fed?

The engine-driven high-pressure fuel pump receives fuel from the engine-driven low-pressure fuel pump. The role of the low-pressure pump is essential, as it ensures that the fuel reaches the high-pressure pump at the required flow and pressure. This is crucial for maintaining the proper fuel delivery to the engine, allowing it to operate efficiently and effectively.

In this context, the high-pressure fuel pump enhances the fuel's pressure to enable optimal atomization when injected into the combustion chamber, significantly contributing to engine performance.

Other options do not directly supply the high-pressure fuel pump. The auxiliary fuel pump, for instance, is primarily used as a backup or during certain conditions, not as a direct feed for continuous operation. The gravity feed pump suggests a simpler system that does not apply to the engineering requirements of the T-6's fuel system. Lastly, the concept of a main fuel storage pump does not align with the T-6 fuel delivery system as the pumps involved work in tandem to ensure proper pressurization and delivery of fuel rather than relying on a singular storage pump function.