1. The hiking instructor advises the hikers on 1) how to cook food on a fire. 2) what to wear on the hiking trip. 3) how to find the way through the forest.

Решение:

В тексте сказано: "The hiking instructor advises the hikers on how to find the way through the forest." Это соответствует третьему варианту ответа.

Ответ: 3) how to find the way through the forest.