Which sign would warn a driver about the presence of construction workers on the roadway?

The correct choice highlights a specific sign that directly alerts drivers to the presence of construction workers in the area. Such signage is crucial for ensuring the safety of both the workers and motorists. A sign indicating "Workers Present" conveys a clear warning that there are individuals working on or near the roadway, prompting drivers to exercise caution and adjust their driving behavior accordingly.

In contrast, other signs listed, while related to roadway conditions, do not specifically denote the presence of construction workers. For example, a "Lane Shift" sign indicates a change in lane alignment but does not necessarily imply that workers are present. Similarly, a "Road Closed Ahead" sign informs drivers about an obstruction ahead but does not specify worker activity. The "Flagger Ahead" sign indicates that a person will be managing traffic, which may imply that work is occurring, but it is less direct than stating that workers are present. Hence, the precise warning of "Workers Present" is the most immediate and relevant to ensure awareness of construction personnel on the roadway.