What is the primary rule for night driving regarding headlight usage when meeting oncoming traffic?

1. Switch from high-beam (main) headlights to low-beam (dipped) headlights in good time, before your lights can dazzle the approaching driver.
2. Maintain high beams to force the oncoming driver to slow down.
3. Switch off all lights completely until the oncoming car passes.
4. Flash high beams continuously.