In Their 30- Year Studies of Darwin's Finches,the Grants Have

In their 30- year studies of Darwin's finches,the Grants have discovered that while the medium ground finch and cactus finch occasionally form hybrids,these hybrids

A) reproduce with the parent species,showing that ground finches and cactus finches are all one species.
B) usually die before hatching.
C) are unable to produce a song and are therefore unable to find a mate.
D) can only survive during wet years when there are plenty of small seeds.