Correct option is D
The correct answer is (d).
The species-specific songs sung by male grasshoppers to attract conspecific females are a form of premating reproductive isolation. This type of isolation prevents interbreeding between different species by attracting only females of the same species. The song functions as a mechanism to ensure that mating occurs only between individuals of the same species, hence preventing cross-species fertilization. This is a clear example of premating isolation, which acts before fertilization.
Incorrect options-
Option (a) postmating and prezygotic: Postmating isolation occurs after mating, which is not the case here; The song is clearly not a postmating barrier, so postmating isolation is not involved.
Option (b) postzygotic: Postzygotic isolation happens after fertilization, such as hybrid inviability or sterility, which is irrelevant to song-based mate choice.
Option (c) premating and postzygotic: This combination is incorrect because the song is a premating barrier; there is no mention of any postzygotic mechanism related to songs
