Answer: Option A
The embryo in the mother's womb cannot eat or drink anything from the outer world. It gets its nutrition from the placenta that is attachment found between the mother and embryo.
The nutrients and gases pass from the mother to embryo in following order. Maternal blood pool ; chorionic villus ; umbilical vein.
In this way the nutrients and gases are carried to the fetus and waste products are taken back through this umbilical cord back for purification.