Here's a problem to solve: In the summer, the Arctic fox's fur is dark gray or brown. In the winter, its fur is white. The changes in color enable the fox to

Among the 4 following options, which is the correct answer?

- A: stay dry in the winter.
 
- B: hunt for food at all times.
 
- C: stay warm in the summer.
 
- D: blend in with its surroundings.
 