Imagine an island archipelago where all of the islands are founded by individuals heterozygous at a particular locus. If there is no migration or mutation, and the alleles at the locus are neutral, what do you expect the island population to look like after many generations?
a) some island populations will have a fixed one allele , and the other populations will have fixed the other allele
b) the populations of every island will have fixed the same allele
c) the island populations will have a high levels of genetic diversity at this locus
d) we cannot predict any outcome because genetic drift is a random process