Which of the following is a sign of a work zone?

The presence of orange cones is a widely recognized sign of a work zone. These cones are used to alert drivers and pedestrians that they are entering an area where road work is taking place, indicating potential hazards or changes in traffic patterns. Orange is a color that is specifically designated for construction and maintenance situations, making it easily identifiable. This visual cue is crucial for ensuring safety; it helps drivers to slow down and remain vigilant as they navigate through or around the work area.

In contrast, while stop signs and yield signs serve important roles in regulating traffic, they do not specifically indicate the presence of a work zone. Crosswalks similarly provide crucial pedestrian safety but are not indicative of work activity. Therefore, orange cones are the correct answer when identifying signs related to work zones.