Which of the following is an example of an indirect attack?

An indirect attack involves engaging a fire from a distance rather than directly confronting it. Creating a controlled burn ahead of the fire is a strategic maneuver that establishes a buffer zone. This buffer consumes the fuel between the fire’s advance and the unburned materials, ultimately altering the fire’s behavior and reducing its intensity. This technique also facilitates better control of the fire’s spread by eliminating fuel that would otherwise feed the flames as it moves forward.

The other options represent more direct methods of fire suppression. Wetting the fire directly, using dirt to smother a fire, and setting up fire lines behind the fire’s advance all involve direct contact with the fire itself or work to contain it after it has already reached a specific area. These methods lack the strategic foresight that characterizes indirect attacks, which take into account fire behavior and terrain to effectively manage a fire's progression.