What action should a motorcycle rider take when they see an animal (such as a kangaroo) on the road ahead?

1. Speed up quickly to pass before the animal moves into your path
2. Swerve into the oncoming lane to avoid the animal at all costs
3. Flash your headlights repeatedly to scare the animal off the road immediately
4. Slow down, do not swerve aggressively, be prepared for the animal to move unpredictably, and sound the horn gently