You are a biologist on a trip to an island in the South Pacific. While on the island, you are allowed to collect DNA samples from a local species of rat that resembles a species seen on a nearby continent. If your DNA analysis also indicates the two species are closely related, you might conclude that the evolution of the two separate species was an example of _____ speciation through _____.
a. allopatric; dispersal
b. sympatric; dispersal
c. allopatric; vicariance
d. sympatric; vicariance