Allopatric speciation can be defined as the speciation that occurs when the populations of the same species are isolated from one another due to some geological barrier. When the isolated population is put under different selection pressures, it will lead to the evolution of the genetic pool in the isolated population and speciation will occur.
Similarly, geographical isolation from the parent population, genetic drift, and different mutations in the isolated population will lead to speciation. However, if there is continuous gene flow between the isolated and parent population, then the speciation will not occur.
Hence, the correct answer is 'Option C'.
