Which signal indicates that a driver should stop?

The stop sign is a clear visual cue to drivers, indicating that they must come to a complete stop. When approaching a stop sign, drivers are required to halt their vehicle to ensure the safety of themselves and others on the road. This sign is universally recognized and mandates that drivers check for oncoming traffic or pedestrians before proceeding.

In contrast, turn signals are used by drivers to communicate their intention to make a turn, rather than to indicate the need to stop. A left or right turn signal informs others of the direction in which the vehicle intends to maneuver, but does not imply that the driver must stop their vehicle. A yield sign indicates a decrease in speed and the need to give way to other traffic, but it does not require a complete stop unless necessary. Therefore, the stop sign is the definitive signal for requiring a complete stop, which makes it the correct choice in this scenario.