So confused and pls ignore what i marked but pls help

When the grand canyon formed many small mammal population were divided. some members of the population were on one side and others are on the other, therefore, they were no able to mate with one another. over time this separation and inability to mate with one another led to the emergence of new species. this type of speciation is called a) sympatric speciation. b) allopatric speciation. c) parapetric speciation. d) peripatric speciation.