What does the YIELD sign mean at a roundabout?

Answer: A — Vehicles entering the roundabout have the right of way

A yield sign at a roundabout means that vehicles entering the roundabout must give way to vehicles already in the roundabout. This is to ensure a smooth flow of traffic and prevent accidents. Option B is incorrect as it goes against the concept of a roundabout where traffic is meant to flow continuously. Option C is incorrect because although it's important to proceed cautiously, taking too much time can cause disruptions and lead to confusion among drivers. Option D is also incorrect as ignoring a yield sign can result in a collision. Therefore, option A is the most appropriate and safe approach when approaching a roundabout with a yield sign.