guys.. i need help.. my science teacher expects me to know how to do work when I wasnt there when he explained it and I was homeschooled last year so I didnt learn it... so can someone tell how t. f I am supposed to do a 2x2 punnett square when he didnt explain it to me

During crossing-over, a. genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles. b. nonsister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. c. one homologous chromosome of a tetrad is exchanged with another tetrad, resulting in new combinations of alleles. d. sister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. e. genetic material is exchanged between sister chromatids, resulting in new combinations of alleles.