In comparison to a main switchboard for a DC electrical distribution system, a main switchboard for an AC electrical distribution system requires the use of which of the following devices, whereas a DC main switchboard does not?

Correct Answer: Option C — Frequency meter, power factor or reactive power meters, and synchronizing lamps or synchroscope

AC distribution systems require complex synchronization, frequency regulation, and power factor monitoring. Per IEEE 45 and 46 CFR Subchapter J, AC main switchboards demand frequency meters, power factor indicators, and synchroscopes or lamps, which are unnecessary on DC systems.