Final answer:
Increased snowfall would likely cause reindeer to move to other areas to compete for resources.
Step-by-step explanation:
Increased snowfall during the entire winter in southern areas would likely cause reindeer to move to other areas to compete for resources (Option D).
Reindeer are adapted to live in cold environments and can survive in snowy conditions. However, if the snowfall increases significantly, it may limit the availability of food and make it more difficult for the reindeer to find resources. In order to find enough food to survive, the reindeer may need to move to areas where there is less competition for resources.
For example, if the snowfall increases in the southern areas where the reindeer are currently living, they may move northward to areas where there is less snow and more food available. This migration would allow them to find enough resources to survive the winter.