A restaurant hood must be protected by which of the following systems?

In a restaurant setting, the primary concern is safety, especially when it comes to kitchen operations where flammable materials and heat are prevalent. A fire suppression system is essential because it is specifically designed to detect and extinguish fires that may occur in cooking areas, particularly under hoods where grease can accumulate and ignite.

Fire suppression systems utilize a combination of chemicals, typically foam or wet chemical agents, that are effective in combating fires fueled by cooking oils and fats, which are common in restaurant kitchens. These systems are activated automatically when a fire is detected, ensuring rapid response and minimizing the potential for extensive damage or injury.

While smoke detectors, ventilation systems, and cleaning systems serve important functions in maintaining safety and air quality, they do not directly suppress fires. Smoke detectors can alert personnel to the presence of smoke but do not extinguish fires. Ventilation systems are crucial for controlling smoke and maintaining air quality and temperature but also lack the capability to put out fires. Cleaning systems help in preventing grease buildup, which is a contributing factor to kitchen fires, but they do not actively engage in fire suppression.

In summary, a fire suppression system is specifically required to protect restaurant hoods from the hazards posed by kitchen fires, making it the correct choice in this context.