A decrease in level of estrogen and progesterone causes
A. A Loss of endometrium
B. Growth of dilation of the endometrium
C. Release of ova from ovaries
D. Constriction of uterine blood vessels leading to sloughing of the uterine epithelium

Hint: Hormones are the chemical messengers where this connects the endocrine system of the body to the nervous system, and most hormones are under the control of the brain, and the hormones which are given above are sex hormones, and they play a very important role in pregnancy of females.

Complete answer:
Estrogen and progesterone are the hormones that are released by the ovaries, and they are called female sex hormones, even though they are also present in males in Small amounts.
Both of these hormones play an important role in regulating the menstrual cycle and maintaining the pregnancy and overall these hormones are important to maintain the sexual nature and reproductive health of the females.
Estrogen hormone is the one that is responsible for obtaining the female secondary sexual characters such as breast and maturation of ovules during puberty.
Estrogen is mainly present in three forms such as Estradiol, estrone, and estriol where they have different functions.
In females, if the person once reaches puberty, the hypothalamus of the brain stimulates the ovaries to release these hormones, by which the ovulation occurs which means the release of mature ovules from the ovary.
If the fertilization of the ovule takes place, both of the hormones estrogen and progesterone increase in the levels to maintain pregnancy and progesterone prepares the uterus walls for the implantation.
If the fertilization does not occur in one day, then these hormone levels fall, which causes the shedding of uterine endometrium that initiates the menstruation where the uterine epithelium and ovule are released in the form of menstruation.
So the correct option is D.

Note: ning the pregnancy and menstruation, in the case of pregnancy this hormone is increased in their levels, while If pregnancy not happens, then these hormones decrease in the levels in the body that initiate the menstruation.