How do the Jet pumps operate when the L/R switch is in the OFF position?

When the left/right switch is in the OFF position, the motive flow shutoff valve closes, preventing any flow of fuel to the jet pumps. This is crucial for ensuring that the pumps do not operate when they are not needed, thus safeguarding against potential fuel system issues or unintended fuel transfer. By closing the motive flow shutoff valve, the system effectively isolates the jet pumps from the fuel source.

In contrast, the other choices present scenarios that do not accurately reflect the state of the jet pumps with the switch in the OFF position. Continuous operation of the pumps would lead to unnecessary fuel movement, which is undesirable when the system is intended to be inactive. Keeping the system active contradicts the design of the fuel system, where shutting off the switch should deactivate the pumps and isolate the flow. Lastly, switching to manual control would imply that the pumps are still operational and can be controlled, which is not the case when the switch is OFF.