Extra structure which provides nutrition to embryo is
A) Umbilicus
B) Chorion
C) Placenta
D) Amnion

Hint: An embryo implants itself in the walls of the uterus. By this adhesion, the embryo receives the oxygen and nutrients from its mother and is able to grow.

Complete answer:
To answer this question, we must know the function of the uterus during reproduction.The foetus stays connected in the uterus till the child's birth. A temporary organ called the placenta develops in the wall of the uterus. The fetus gets connected to the placenta by umbilical cord. The umbilical cord has blood vessels through which the fetus receives the nutrient, oxygen, antibodies, thermal regulation from the placenta.
Umbilicus- They are the blood vessels which connect the placenta and the foetus.
Chorion- It is the outermost foetal membrane around the embryo. It is an outer membrane around the yolk sac.
Amnion-It is the membrane that closely covers the embryo when it is first formed. It gets filled with fluid and becomes a amniotic sac which provides a protective environment to the growing embryo.

Additional Information:After delivery, the uterus continues to contract. These contractions move the placenta for delivery as well. Placenta is delivered along with the baby during labor contractions.

The correct answer is (C). Extra structure which provides nutrition to the embryo is placenta.

Note:Placenta is the lifeline between the mother and the baby. It is an endocrine gland which also provides all the necessary hormones to the baby which is necessary for maintaining a healthy pregnancy.