What type of system requires stretching back out by running pulley or prusik closest to the load after raising?

The correct answer, which identifies a mechanical advantage system, is appropriate because this type of system is designed to lift heavy loads with a reduced amount of force applied by the rescuer. In a mechanical advantage system, multiple pulleys or configurations are used to distribute the load and effectively increase the lifting capacity.

When operating such a system, it is necessary to adjust the rigging post-raise to ensure that the load remains secure and properly positioned. This is where the practice of stretching back out the system by running the pulley or prusik closest to the load comes into play. By doing this, it allows for any slack in the system to be removed and maintains the integrity of the lift, ensuring that the load does not drop or shift unexpectedly.

The other types of systems mentioned, while useful in their own contexts, do not require this specific adjustment method. A winch system typically uses mechanical means for lifting without the need for manual adjustments in the same way. A block and tackle system involves a set arrangement of pulleys and can often reduce effort when lifting, but does not emphasize the need for post-raise adjustments as the mechanical advantage system does. A simple pulley system offers minimal mechanical advantage and is quite straightforward, lacking the complexity that necessitates