Final answer:
The sign that indicates that a flagger is ahead and that you should slow down and be prepared to stop is the Flagger Ahead sign.
Step-by-step explanation:
The sign that indicates that a flagger is ahead and that you should slow down and be prepared to stop is the Flagger Ahead sign.
This sign typically consists of an image of a person holding a flag and is placed in areas where construction or roadwork is taking place. It alerts drivers to the presence of a flagger who will guide traffic and may require them to stop temporarily.