It is currently believed that apple maggot flies are undergoing a divergence into two separate ...

It is currently believed that apple maggot flies are undergoing a divergence into two separate species.
 
  Two hundred years ago these maggot flies laid their eggs only on the hawthorn fruit, but after apples were introduced in the Americas, some maggot flies started laying their eggs on apples. Today, females generally lay their eggs on the type of fruit they grew up in, and male flies end up mating on the type of fruit they grew up in. Therefore hawthorn flies mate with hawthorn flies and apple flies mate with apple flies. If genetic changes between the hawthorn maggot flies and the apple maggot flies continue until the flies are different species, this would be an example of
 
 A. allopatric speciation.
  B. parapatric speciation.
  C. sympatric speciation