Which unit is commonly used to assist in electrical tasks while the aircraft is on the ground?

The correct answer is the Ground Power Unit, as it is specifically designed to provide electrical power to an aircraft while it is on the ground. This unit can supply electricity for various systems, allowing crew members to perform essential tasks such as running onboard equipment, starting up the aircraft's engines, and maintaining systems without relying on the plane's own power supply.

The Ground Power Unit is an essential piece of ground support equipment that enhances efficiency and safety during pre-flight checks and maintenance activities. It helps prevent battery drain and ensures that all systems are functioning correctly before departure.

The other options do not fulfill the same role as the Ground Power Unit. The Ground Control Unit typically refers to systems involved in directing ground operations but does not provide electrical power. The General Operations Manual is a document that outlines procedures and policies for airline operations, and the Guest Service Area is focused on passenger services rather than aircraft electrical needs. Thus, the Ground Power Unit stands out as the correct choice for providing electrical assistance on the ground.