Final answer:
Electric power cords with 3-prong electrical plugs provide grounding for safety, creating a protective low-resistance path to earth and prevent severe shocks in case of insulation failure or appliance malfunctions (B).
Step-by-step explanation:
Electric power cords are typically equipped with 3-prong electrical plugs for grounding for safety. The third prong is a ground wire that creates a low-resistance path to the earth, which is necessary to prevent severe electric shocks in case of insulation wear on live/hot wires or malfunctioning appliances. In addition, it ensures that in the event of a fault, a circuit breaker will trigger, necessitating the repair of the appliance to prevent accidental electrocution, especially in areas where an effective connection to the earth through water is present.
Some appliances still come with two-prong plugs because they have nonconducting cases and are deemed doubly insulated, mitigating the need for a separate ground wire.
The three-wire system, which includes a connection for live/hot, neutral, and earth/ground wires, is designed to guard against thermal and shock hazards, and with a three-hole outlet, the standard three-prong plug can only be inserted in one way to ensure proper function.