**Core Concept**
Gonadotropin-releasing hormone (GnRH) analogues are a class of medications used to treat endometriosis by inducing a temporary menopausal state, leading to decreased estrogen levels and subsequent endometrial decidualization and atrophy. This pharmacological approach is based on the understanding that endometriosis is an estrogen-dependent condition.

**Why the Correct Answer is Right**
GnRH analogues work by initially stimulating the pituitary gland to release gonadotropins (LH and FSH), which in turn stimulate the ovaries to produce estrogen. However, with continuous administration, GnRH analogues induce downregulation of GnRH receptors, leading to decreased secretion of gonadotropins and subsequently a decrease in estrogen production. This reduction in estrogen levels inhibits the growth and proliferation of endometrial tissue, providing relief from symptoms associated with endometriosis. The most commonly used GnRH analogue in the treatment of endometriosis is leuprolide.

**Why Each Wrong Option is Incorrect**
**Option A:** LH (luteinizing hormone) is one of the gonadotropins responsible for stimulating ovulation and estrogen production, but it is not used to treat endometriosis due to its role in promoting estrogen production.
**Option C:** Medroxyprogesterone acetate (MPA) is a progestin used in the treatment of endometriosis, but it works differently than GnRH analogues by inducing decidualization and atrophy of the endometrium through progestogenic effects, rather than reducing estrogen levels.
**Option D:** FSH (follicle-stimulating hormone) is another gonadotropin involved in the regulation of ovarian function, but like LH, it is not used to treat endometriosis due to its role in promoting estrogen production.

**Clinical Pearl / High-Yield Fact**
It's essential to note that GnRH analogues can cause a temporary menopausal state, leading to symptoms such as hot flashes, vaginal dryness, and bone loss. Therefore, these medications are typically used for a limited duration (usually 6-12 months) to minimize these side effects.

✓ Correct Answer: B. GnRH analogues