Correct option (d) Amnion
Explanation
Amnion is an extra embryonic membrane that surrounds embryo in reptiles, birds and mammals. It provides a kind of private aquarium to the embryo and protects it from mechanical shock and desiccation.
Chorion (serosa) is the outermost extra embryonic membrane in reptiles, birds and mammals. It surrounds the whole embryonic system of embryo.
Yolk sac contains yolk in reptiles and birds. In mammals yolk sac is also know umbilical vesicle. It is connected to enteron of embryo by a slender yolk stalk.
