A nurse is assisting in the care of a client at 10 weeks of gestation who asks how the biological sex of the fetus is determined. Which of the following responses should the nurse make?

"Biological sex is determined when the zygote experiences implantation"

“Biological sex is determined by the specific combination of sex chromosomes present in the DNA.”

“Biological sex is determined when cell division takes place within the foramen ovale”

"Biological sex is determined when the blastocyst forms during fertilization."