The correct option is C 4
There are four fetal membranes in man as:
Amnion: It protects the embryo from desiccation in the sac filled with amniotic fluid.
Yolk sac: It contains yolk which provides nutrition from developing embryo.
Chorion: It is an extraembryonic layer which helps to form placenta during the enbryo developement.
Allantois: It stores metabolic wastes of the embryo.
Thus, the correct answer is option C.