Which of the following occurs during synapsis of meiosis:

W) non-sister chromatids of homologous chromosomes cross over

X) sister chromatids of homologous chromosomes cross over

Y) non-sister chromatids of non-homologous chromosomes cross over

Z) sister chromatids of non-homologous chromosomes cross over
W) NON-SISTER CHROMATIDS OF HOMologous CHROMOSOMES CROSS OVER