Answer:
The correct answer would be option a.
Explanation:
The placenta is the organ that originates or arise and implant in the mother's uterus during the period of pregnancy.
The fetus is attached to the placenta through the umbilical cord.
Through the umbilical cord and placenta, carbon dioxide and waste products and from the fetus are transported to the mother's circulation to be eliminated.
Thus, the correct answer is option a.