Under Article 81 of the Implementing Regulations, when driving on an expressway in fog, rain, snow, or dust with visibility under 200 meters (the '261' rule), what are the maximum speed and minimum following distance requirements?

1. Speed must not exceed 40 km/h, following distance must be at least 50 meters, and hazard flashers must be turned on
2. Speed must not exceed 80 km/h, following distance must be at least 150 meters
3. Speed must not exceed 60 km/h, following distance must be at least 100 meters, and fog lights, low beams, and position lights must be turned on
4. Speed must not exceed 20 km/h, and the vehicle must exit the expressway immediately