What role does the earth wire play in the safety of domestic appliances with metallic bodies?

The correct option is "It provides a low-resistance path for leakage current".

In domestic electrical wiring, appliances with metallic outer bodies (such as refrigerators, ovens, and washing machines) pose a risk of electric shock if an internal live wire accidentally touches the metal casing due to wear or damage. This is known as a current leak.

To prevent electric shocks, the metal body of the appliance is connected to the earth wire. The earth wire is a safety wire that leads directly into the ground and has extremely low electrical resistance. If a fault occurs and current leaks to the metallic body, the current will preferentially flow through the earth wire because it provides a much easier, low-resistance path compared to a human body touching the appliance.

This rapid flow of excess current through the earth wire to the ground instantly creates a short circuit, which dramatically increases the current in the circuit. This surge in current exceeds the rating of the fuse or circuit breaker, causing the fuse to melt or the circuit breaker to trip, thereby safely disconnecting the power supply to the faulty appliance.