When driving in winter conditions through snowy or icy mountain passes (such as the Salang Tunnel approaches), what equipment is essential?

1. Tire snow chains, antifreeze in the cooling system, ice scraper, warm blankets, and a tow rope
2. Extra air in the tires to make them hard
3. Summer performance tires with smooth tread
4. No special equipment is needed if driving an all-wheel-drive vehicle