Option 1 -> Black insulation correctly identifies a neutral wire in standard electrical systems.
Option 2 -> This accurately describes household AC power supply (220V/50Hz) with red insulation for the live wire.
Option 3 -> While the earth wire function is correct, the color is WRONG - earth wires have green or green/yellow insulation, NOT pink.
Option 4 -> Copper is indeed the standard material for household electrical wiring due to its excellent conductivity.
Hence, Option 3 -> The earth wire (ground wire) is always identified by green or green/yellow striped insulation for safety standardization worldwide, never pink. This color coding is critical for safety and is internationally standardized to prevent electrical accidents -> correct