Answer:
c. founder effect
Explanation:
The founder effect occurs when there is a loss or reduction of genetic variation when a new population is produced or established by a few number of individuals from a large population. In other words, a new colony is formed from a large population. This could result to differences in phenotype ad genotype of the new population from the original population.
The gene pool of the new population is also affected. The small group of squirrels that separated from the the large population during the flood to form a new population, is an example of founder effect.
