During metaphase II of meiosis, what is the key event that occurs in each haploid cell?

• A. Sister chromatids separate and move to opposite poles of the cell.
• B. Individual chromosomes (each still consisting of two sister chromatids) align at the metaphase plate.
• C. Homologous chromosome pairs (tetrads) align at the metaphase plate and undergo crossing over.
• D. Nuclear envelopes reform around two sets of chromosomes and cytokinesis produces four haploid cells.

Answer: (B)