The answer is A. Sound System. A Sound System is generally not considered a core part of an electrical plan because it relates more to audio equipment installation and acoustics, not the fundamental electrical infrastructure.An electrical plan mainly focuses on how electrical power is supplied, distributed, and used within a building or space. The major parts include,Lighting System - Shows where lights will be installed and how they are powered.Electrical Requirements - Details the total power needs and specifications for the building or area.Electrical Distribution System - Describes how electricity is routed through circuits, panels, and wiring to different parts of the building.