Final answer:
The neutral wire connected to the 120V AC shoreline power should be ungrounded to provide a safe return path for the current and complete the circuit.
Step-by-step explanation:
The neutral wire connected to the 120V AC shoreline power should be ungrounded in order to provide a return path for the current to complete the circuit. The neutral wire is connected to ground at the voltage source and the user's location, which forces it to be at zero volts relative to ground. This grounding ensures safety, as the neutral wire is safe to touch even if its insulation is missing. The two ground connections on the neutral wire supply an alternative path through the ground to complete the circuit, while the hot wire supplies voltage and current to operate the appliance.