The fuel oil back pressure regulator on the fuel system shown in the illustration, returns fuel to the which of the following? Illustration GT-0021

Correct Answer: Option D — Booster pump discharge.

The fuel oil back pressure regulator maintains a constant pressure at the fuel control inlet by bypassing excess fuel. Returning this flow to the booster pump discharge ensures a stable supply pressure regardless of engine demand, preventing cavitation and maintaining the required fuel flow characteristics for the engine's operation.