When materials are being hoisted to an upper level, a tag line is used to:

Using a tag line when hoisting materials serves the primary purpose of helping to control the load during the lifting process. A tag line is a rope or line that is attached to the load and used by personnel on the ground or at another location to guide and stabilize the item being lifted. This is especially crucial in ensuring the load does not swing uncontrollably, which can happen due to wind or movement of the crane or lifting equipment.

Proper use of a tag line enables the rigger or operator to maneuver the load safely and accurately into position, minimizing the risk of collisions with obstacles or workers nearby. This control is vital for maintaining the safety of the operation, as well as for protecting the integrity of the load being lifted.

In contrast, other options focus on aspects that do not define the primary function of a tag line. For example, while it might seem like a tag line could help raise the load, it is the lifting mechanism that primarily accomplishes that task. Additionally, a tag line is not intended to stop a process or prevent materials from falling; its role is to provide control during the lift rather than act as a safety device against falls. Thus, the function of a tag line clearly aligns with the purpose of load control.