Answer: d. tundra
Step-by-step explanation:
Polar bears are present only in the Arctic tundra biome. The most important areas for polar bears in the arctic are are the edges of pack ice where the wind and water interact, which createsa constant refreezing and melting network of leads (open spaces in the sea ice) and ice patches.
A polar bear has a fat layer under the skin that helps it stay warm and the big paws help a polar bear walk through the snow.
Hence, the correct option is D. Tundra.