To prevent static charge in a fuel tank, what height of liquid must be removed?

The correct choice indicates that removing 1 meter of liquid from a fuel tank is crucial for mitigating the risks associated with static electricity generation. When fuel is moved or agitated, particularly during loading and unloading, static electricity can accumulate due to the movement of fuel against the walls of the tank or other surfaces. This static charge, if allowed to build up, can potentially create a spark, leading to ignition and fire hazards.

By ensuring that a minimum height of 1 meter of liquid remains in the tank, the risk of significant static charge accumulation is minimized. This height acts as a buffer to help dissipate static charges more effectively and prevent dangerous situations. Most safety protocols in the marine and industrial sectors emphasize maintaining this level to provide a safety margin against static discharge.

Other height options may either not be sufficient to ensure safety or go beyond what is necessary, potentially leading to inefficiencies or unnecessary complications in operations without providing additional protective benefits against static discharge. Hence, the choice of 1 meter is aligned with industry best practices for safety in fuel storage and handling.