The correct option is
B I, II and III
The reproductive phase in human females is regulated by changes in hormonal levels or cycles which is known as the menstrual cycle. GnRH refers to gonadotropin releasing hormone. It is secreted by the hypothalamus. It acts on the anterior pituitary and stimulates the release of gonadotropin hormones i.e. LH (luteinising hormone) and FSH (follicle stimulating hormone).
Estrogen and progesterone are female sex hormones produced inside the female gonads i.e. ovaries. Estrogen is not the name of a single hormone. It is a combined name given to a group of hormones.
During the follicular phase, the levels of pituitary hormone FSH and LH increase gradually in the first 7 days. FSH stimulates several ovarian follicles to grow and develop. These growing follicles secrete low levels of estrogen and inhibin. Around day 6-7, the pituitary hormone LH stimulates the maturation of one of the growing follicles. The mature follicle begins to secrete high levels of estrogen and inhibin, which decreases the secretion of FSH by the anterior pituitary.
In the luteal phase, the mature Graafian follicle transforms into a corpus luteum. Corpus luteum secretes progesterone. Progesterone also suppresses the secretion of FSH in greater amounts. This is clearly visible in the graph. In the luteal phase, the levels of LH and FSH are almost the same as they were in the follicular phase. But, in the luteal phase, there is no development of follicles like in the follicular phase. It is because the increased level of progesterone has suppressed the effect of FSH.
LH and FSH are both gonadotropins released by the anterior pituitary under the influence of GnRH from the hypothalamus. So, LH levels do not affect the FSH levels.