digs up food walks in deep snow climbs rocky cliffs runs under bushes
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A bird called a ptarmigan has feathered feet. The feathers on the feet of the ptarmigan are most helpful when this bird ___.
Possibilities:
- digs up food
- walks in deep snow
- climbs rocky cliffs
- runs under bushes

walks in deep snow