Answer:
The correct answer would be option D.
Tundra is a biome in which trees growth is hindered by the low temperature of the region.
The tundra region remains cover with ice until summer appears.
The vegetation may include shrubs, grasses, lichens et cetera.
Due to current environmental changes, there is an increase in tree cover in the region.
The increased tree cover attracts the red foxes from the south.
As red foxes are omnivores in nature, an increase in tree covers would increase the amount of food available. For example, berries, fruits, grasses, birds, squirrels, mice, and rabbits.
