Under Article 81 of the Implementation Regulations, when expressway visibility is LESS THAN 100 METERS, what are the mandatory operational rules?

1. Speed must not exceed 40 km/h, following distance must be at least 50 meters, and turn on fog lights, low beams, clearance lamps, tail lamps, and hazard warning flashers (危险报警闪光灯)
2. Speed must not exceed 60 km/h, distance at least 100 meters, and keep hazard flashers off
3. Maintain 80 km/h to pass through the fog bank as quickly as possible
4. Pull over onto the active fast lane and await police rescue