The verb ります (のぼります) means "to climb (a mountain)".
This question is actually to test the continuity of the previous verb when two verbs are put together. Generally speaking, when two verbs are put together (different from the corresponding verbs), the former verb should become a shape with convenient pronunciation, which is commonly called て shape.
Then the prototype of the verb before "Deng ります" is "く", which is a five-paragraph verb, and the five-paragraph verb at the end of く becomes "ぃて", so choose 2 in this question.
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