-
A
The device is turned off
-
B
A grounded device has a third wire connecting the metal chassis to earth ground — providing a safe path for fault current to flow to ground rather than through a person who touches the device
-
C
Grounding increases the device's power consumption
-
D
It means the device is waterproof
Why this is the answer
ELECTRICAL GROUNDING SAFETY: If a wire inside an appliance shorts to the metal chassis (due to insulation failure), without grounding the chassis becomes energised at line voltage — touching it would cause electrocution. With GROUNDING: The third prong on a plug connects the chassis to earth ground via the building's grounding system; fault current travels the low-resistance path to ground, tripping the circuit breaker; the chassis voltage stays near zero. GROUND FAULT CIRCUIT INTERRUPTERS (GFCIs): Required in bathrooms, kitchens, and outdoor outlets — they detect even tiny ground fault currents (5 mA) and trip within 1/40 of a second, preventing electrocution faster than a circuit breaker.
Source: ASVAB EI, Electrical Safety — Grounding