Crossing Over Is One of the Most Important Events in Meiosis

Crossing over is one of the most important events in meiosis because

A) it produces new arrays of alleles on chromosomes.
B) homologous chromosomes must be separated into different daughter cells.
C) the number of chromosomes allotted to each daughter cell must be halved.
D) homologous chromatids must be separated into different daughter cells.
E) it is the mechanism through which twins are produced.