Question

Fly species w, found in a certain part of the island, produces fertile offspring with species y. species w does not produce fertile offspring with species x or z. if no other species can hybridize, then species w and y

Answer 1

Considering the answers;
A. are still sibling species
B. shared a common ancestor more recently with each other than either did with the other two species
C.May merge into a single species if their hybrids remain fertile over the course of many generations.
D. A and B only
E. A, B, and C
The answer will be E. 
If no other species can hybridize, then species W and Y are still sibling species, shared a common ancestor more recently with each other than either did with the other two species and also may merge into a single species if their hybrids remain fertile over the course of many generations.