Progesterone antagonist is:

Correct option is B

Ans. (b) Sol. The correct answer is (b) Mifepristone.
Mifepristone is a progesterone antagonist that works by blocking the effects of progesterone, a hormone essential for maintaining pregnancy. It is commonly used in medical abortion, as it prevents the continuation of pregnancy by inhibiting the action of progesterone on the uterine lining.
Explanation of each option:
· (a) Misoprostol: Misoprostol is a medication that induces uterine contractions and is often used in combination with mifepristone for medical abortion. It is not a progesterone antagonist, but rather a prostaglandin analog.
· (b) Mifepristone: Correct answer. Mifepristone is a progesterone antagonist, used to block the action of progesterone and induce abortion.
· (c) Regesterone: Regesterone is a synthetic progestin used to support pregnancy or regulate menstrual cycles, but it is not a progesterone antagonist.
· (d) Prostaglandins: Prostaglandins are hormone-like substances involved in inducing uterine contractions and other physiological functions. They are not progesterone antagonists.
Thus, Mifepristone is the progesterone antagonist.