During meiosis chromosome pairs randomly line up along each side of the cell equator this arrangement mixes up the chromosomal combinations which what?

During meiosis, chromosome pairs randomly line up along each side of the cell equator. This arrangement mixes up the chromosomal combinations, which  

A.helps ensure reproductive success.  

B.helps create and maintain genetic diversity.

C.helps maintain all of the previous generation's characteristics.

D.helps ensure an equal number of males and females in the next generation.