A) Due to the joining of the two gametes (sperm cell and egg which both have 23 chromosomes, the fertilised egg has 46 chromosomes) and because a skin cell is a normal cell (not a sex cell) it has 46 chromosomes.
You can automatically eliminate choice B because a zygote is the name for the cell produced when a sperm cell and egg joins, meaning it now has both 23 chromosomes from each of the sex cells, meaning it has 46 chromosomes. Sperm cells only ever have 23 chromosomes.
