NASA Scientists Send a Small Population of Dogs to a New

NASA Scientists send a small population of dogs to a new planet in order to test if it will be hospitable for human colonization. Through a random lottery, only Great Dane and St. Bernard dog breeds are sent, and the resulting population consists of tall, longhaired dogs. After 100 years these dogs return to earth and are no longer able to mate with earth dogs. This scenario is an example of

A) allopatric speciation through genetic drift.
B) allopatric speciation through natural selection.
C) sympatric speciation through genetic drift.
D) sympatric speciation through natural selection.