Answer:
C) the amount of snow cover varied over the years.
Step-by-step explanation:
The most likely answer is that the amount of snow cover varied over the years. In this example, the rabbits are white because of an adaptation. Having white fur allows them to better blend with their environment. However, if over the years, the coloration of the rabbits was mostly gray, this most likely means that their adaptation is no longer useful. It is likely that snow cover decreased, which meant that being white became a disadvantage.