Which Statement Is Correct About the Placenta

Which statement is correct about the placenta?

A) The placenta allows for free exchange of blood from the fetus to the mother but not the other direction.
B) The placenta allows for free exchange of blood from the mother to the fetus but not the other direction.
C) The placenta allows for a limited exchange of gases from the fetus to the mother but a free exchange from the mother to the fetus.
D) The placenta does not allow the exchange of blood between the fetus and mother but allows the exchange of gases.
E) The placenta does not allow the exchange of blood or gases between the fetus and mother.