The Middle East blind mole rat (Nannosplalax ehrenbergi) lives in the Upper Galilee Mountains of Israel. Two groups of these mole rats live in the same region, but scientists discovered that there is a 40% difference in mitochondrial DNA between these two groups. These rats do not seem to interbreed in the wild. This is an example of
(A) allopatric speciation
(B) sympatric speciation
(C) pre-zygotic barrier
(D) hybrid zone