The correct answer is A. Allopatric.
Species that occur in different geographical regions separated by a special barrier are called allopatric species. This barrier can be a mountain range, a desert, or an ocean. Allopatric species are not able to interbreed because they are separated by a physical barrier.
Sympatric species are species that occur in the same geographical region. They can interbreed, but they do not because they are reproductively isolated. This means that they have different mating habits, or they produce different types of gametes (sperm or eggs).
Sibling species are species that are very closely related. They may look very similar, but they are not able to interbreed. This is because they have different mating habits, or they produce different types of gametes.
None of the above is not a correct answer.