Which of the following signals is used to indicate a stop during crane operation?

The signal used to indicate a stop during crane operation is essential for ensuring safety and clear communication among operators and crew members. The choice indicating a stop is straightforward, as this signal directly conveys the need for immediate cessation of all movements, ensuring that everyone involved can take necessary precautions or respond appropriately to changing conditions on site.

Using a clear signal such as "Stop" is critical in preventing accidents and injuries that could arise from uncontrolled crane movements. In high-stress or visually obstructed environments, having a designated signal for stopping allows the operator to swiftly halt operations when needed, whether due to unexpected obstacles, safety concerns, or other directives from the ground crew.

In contrast, the other signals mentioned suggest actions related to movement or adjustments. These signals are important for guiding operations but do not address the immediate need to stop all activities, which is where safety must take precedence. Clear distinctions among the signals help maintain effective communication, which is vital in any rigging and hoisting scenario.