Once the pregnancy (also called gestation) sets in, a woman’s body goes through a series of physiological changes. It is the time during which one or more offspring develop inside the uterus of a woman.
Uterus (B) is the muscular bag at the end of the vagina wherein the embryo implants and develops into a baby.
Cervix (C) is the opening of the uterus, connecting to the vagina. The baby emerges through this aperture and comes out through the vagina, during child birth.
Corpus luteum (D) is a temporary endocrine structure involved in ovulation and early pregnancy.
The options given above have little role in secreting hormones that prepare the breasts for lactation.
Therefore, the options B, C and D are incorrect.
Placenta (A, the connection between mother and child) is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, temperature regulation and waste discard. It produces the hormones that further maintains the endometrium and prepares the breasts for milk production.
Therefore, option (A) is correct.