Answer:
Option D, Gene Flow
Step-by-step explanation:
Gene flow is defined as the flow of genes from one population to other thereby causing variation in the base population. Here the population of mole will have a certain number of genes but its interaction with a foreign species will lead to evolution of population through natural selection and genes of this foreign species will also get mixed with genes of mole population which later on may lead to further variations with in a single set of population inclusive of all .
Hence, option D is correct