What should you do when approaching a roundabout?

When approaching a roundabout, yielding to circulating traffic is essential for maintaining a safe flow of vehicles and preventing accidents. Roundabouts are designed to allow vehicles already in the circle to continue moving without interruption, which improves traffic efficiency and safety. By yielding, you give priority to those who are already circulating, helping to ensure that everyone can enter and exit the roundabout smoothly.

The other options do not align with safe practices at roundabouts. Merging quickly could lead to collisions with vehicles already in the roundabout, and coming to a complete stop without necessity may disrupt the flow of traffic. Additionally, while it's important to follow the designated route, this should not be done without properly yielding to the existing traffic already in the roundabout.