What is the "Z" drag system used for in a rope rescue?

The "Z" drag system is specifically designed to facilitate the horizontal movement of a load with minimal effort. It utilizes the mechanical advantage created by the rope system to efficiently pull a load in a horizontal direction, making it exceptionally useful in rescue scenarios where a victim or equipment needs to be moved sideways, such as out of a crevice or towards a safer location.

The system operates by creating a configuration where the pulling force is redirected effectively, optimizing the effort required for the operation. This is particularly important in situations where the rescuer may be limited by physical strength, or where the load is heavy or awkwardly positioned.

Thus, while other systems might be geared towards different operations, such as securing or stabilizing a load, the "Z" drag's primary function is focused on the horizontal displacement of a load, making option C the correct choice.