During metaphase I of meiosis, what is the key chromosomal event that occurs at the metaphase plate?

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

Answer: (A)