What component supplies electrical power to operate the FMU-139A/B fuze?

The correct component that supplies electrical power to operate the FMU-139A/B fuze is the FZU-48/B initiator. This initiator plays a critical role as it contains the necessary electrical components to activate the fuze upon the required input, enabling it to function effectively in a munition system. The FZU-48/B initiator is designed to produce a reliable ignition source that interacts with the fuze, making it essential for its operation.

While other components like the power cell, electrical capacitor, and battery pack are important in various functionalities within other systems or devices, they do not specifically supply the power necessary for the FMU-139A/B fuze's operation. Each of these components may serve different roles in different contexts but is not the direct source of power for this particular fuze. Thus, the FZU-48/B initiator stands out as the key component required for powering and successfully activating the FMU-139A/B fuze within the munitions system.