Final answer:
A yellow pennant sign with circular arrows signifies a roundabout ahead, where drivers should slow down and yield to circulating traffic, helping to manage traffic densities.
Step-by-step explanation:
A yellow pennant sign with circular arrows indicates a roundabout ahead. This type of road sign is used to inform drivers that they are approaching a circular intersection where traffic flows around a central island in a counter-clockwise direction in countries where traffic drives on the right, or clockwise in countries where traffic drives on the left.
The correct response to the student's question is option c) Roundabout ahead. In a roundabout, drivers should slow down and yield to the traffic already circulating within the roundabout. Roundabouts are designed to improve the flow of traffic with traffic densities and reduce the likelihood of accidents since they eliminate traditional traffic signal needs and encourage a continuous, albeit slower, movement of vehicles.