Which of the following is the MOST appropriate and effective fire suppression method for an...

The most appropriate and effective fire suppression method for an un-staffed computer room is carbon dioxide (CO2). Carbon dioxide is a gaseous clean agent that extinguishes fire by displacing oxygen and reducing the combustion process. Carbon dioxide is suitable for un-staffed computer rooms because it does not leave any residue, damage, or corrosion on the electronic equipment, and it does not require water or other chemicals that could harm the environment or human health. However, carbon dioxide can pose a risk of asphyxiation to any person who may enter the computer room during or after the discharge, so proper safety precautions and warning signs should be in place.

The other options are not as appropriate or effective as carbon dioxide for an un-staffed computer room:

Water sprinkler. This is a common fire suppression method that uses water to cool down and extinguish fire. However, water sprinkler is not suitable for un-staffed computer rooms because it can cause severe damage to the electronic equipment, such as short circuits, corrosion, or data loss. Water sprinkler can also create a risk of electric shock to any person who may enter the computer room during or after the discharge.

Fire extinguishers. These are portable devices that contain a pressurized agent that can be sprayed on a fire to put it out. However, fire extinguishers are not effective for un-staffed computer rooms because they require manual operation by a trained person who can identify the type and location of the fire, and use the appropriate extinguisher. Fire extinguishers can also cause damage to the electronic equipment if they contain water or chemical agents.

Dry pipe. This is a type of sprinkler system that uses pressurized air or nitrogen in the pipes instead of water until a fire is detected. When a fire is detected, the air or nitrogen is released and water flows into the pipes and sprinklers. However, dry pipe is not ideal for un-staffed computer rooms because it still uses water as the extinguishing agent, which can damage the electronic equipment as mentioned above. Dry pipe also has a slower response time than wet pipe sprinkler systems, which can allow the fire to spread more quickly.