During recombination

1)sister chromatids undergo crossing-over with each other.
2)chiasmata hold chromosomes together.
3)one crossover event occurs for each pair of human chromosomes.
4)the synaptonemal complex keeps the sister chromatids together until anaphase ii.

2)chiasmata hold chromosomes together.

Explanation:

Chiasma (pl. Chiasmata): it is the point of contact, the physical union between two non-sister chromatids that belong to homologous chromosomes. In a given chiasma, an exchange of genetic material can occur between both chromatids.

1) is FALSE becasue recombination occurs between chromatids of homologous chromosomes, NOT between sister chromatids.

3) is FALSE because more than one recombination event can occur in a given pair of homologous chromosomes.

4) is FALSE becasue synaptonemal complex keeps homologous chromosomes together, NOT sister chromatids. Additionally, recombination occurs in prophase 1, long before anaphase 2.

i believe the correct answer is d