How does random fertilization add to the genetic variation?

Genetic variation is also introduced by random fertilization of the gametes produced by meiosis. Any of the genetically unique sperm generated by a male may fertilize the genetically unique egg produced by a female. During metaphase I, the homologous pairs of chromosomes are aligned along the metaphase plate.
So I think that would be B) sorry if I’m wrong

Generally these different species because of their different feeding and nesting habits do not interbreed. In a series of dry seasons the differences in beak size increases causing further separation of the different types of finches.

Explanation: