Although Populations of North American Apple Maggot Flies Are Not

Multiple Choice

Although populations of North American apple maggot flies are not geographically isolated,they appear to be in the process of diverging into two new species.Which of the following could be causing speciation between two populations in the lack of geographic isolation?

A) feeding on two different types of food
B) producing fertile hybrids
C) laying their eggs in the same location
D) increased gene flow between them