Read this excerpt from Susan Butcher and the Iditarod Trail. The next morning Seppala prepared to start again, but could find no trace of a land trail. The wind continued to blow almost at hurricane force. Seppala could not even see the front of his team through this total “whiteout.” It was Togo who felt beneath the snow, found the trail, and started for the next relay point.

Which conclusion can be formed based on the information in the excerpt?

Mushers and their dogs have little experience with severe winter storms.
Mushers and their dogs are equally dependent on each other for survival.
Mushers and their dogs depend mostly on their senses of sight on a trail.
Mushers and their dogs often become lost during severe winter storms.