What is the correct course of action in this situation?

Your answer is fully correct. The warning sign indicates a slippery road, usually caused by rain, ice, or leaves. In such conditions, it is important to reduce your speed to maintain control of the vehicle and to avoid abrupt steering movements, as sudden changes in direction can easily cause skidding. Braking hard is not recommended here because it can lead to loss of traction and increase the risk of skidding or losing control. By slowing down gently and steering smoothly, you maximize safety on slippery roads.