PLEASE ANSWER FAST
Option B is correct.
The Placenta is a temporary association between the chorion frondosum (embryonic tissue) and decidua basalis (maternal tissue)
Structure : In humans, the placenta has a disc shape having dark reddish blue or crimson colour,weighs approx.~500 gm of an an average 22 cm in length and 2-2.5cm in thickness with centre being thickest and the edges being the thinnest.
Functions : (a) Placenta connects the developing foetus to the uterine wall and act as an ultra filter of soluble inorganic and organic material , allow nutrient uptake, waste elimination and exchange via the mother's blood supply,fight against internal infection.
(b) It acts as an endocrine gland and synthesises large quantities of proteins and some hormones.