Which of the following is a type of suppression for wildfires?

Class A foam is specifically designed for the suppression of wildfires, making it the correct choice. This type of foam is used to combat Class A fires, which typically involve ordinary combustible materials like grass, wood, and other vegetative matter commonly found in wildland areas. Class A foam works by forming a blanket over the fuel, which cools the fire and suppresses flammable vapors, thereby preventing the fire from spreading further.

In contrast, fire alarms and smoke detectors are primarily designed for detection and alerting purposes within buildings to help occupants evacuate in the event of a fire; they do not extinguish fires. Fire extinguishers are useful in controlling small fires, but there are various classes of extinguishers, and not all are effective against wildfires, which can be extensive and require more specialized methods of suppression like the use of Class A foam. The focus of Class A foam on suppressing fires in outdoor environments with readily combustible materials makes it the most suitable option for this question.