The correct option is B progesterone
The ruptured Graafian follicle transforms into corpus luteum.
Corpus luteum is a temporary endocrine structure that produces large amounts of progesterone and small amounts of estrogen.
Thus, the main function of corpus luteum is production of progesterone.
Progesterone hormone maintains the endometrium of the uterus which is essential for the implantation of the embryo.
Human chorionic gonadotropin (hCG) and human placental lactogen (hPL) are hormones secreted by the placenta.