Which of the following examples best represents the mechanism of evolution known as genetic drift?

a. a farmer consistently chooses the tastiest watermelons to keep seeds from and plant for the next crop.

b. a volcano erupts and lava pours over a population of flowering plants eliminating a large portion of the flowers on the north side of the island while leaving the population of the south side of the island intact.

c. an individual goat migrates across a mountain range to a new population of goats where it breeds and produces offspring.

d. a mutation results in a population of trees that spread their seeds more widely than their peers, causing their population to grow.