**Core Concept:** In an infertile woman with a proliferative endometrial biopsy, the focus is on addressing the hormonal imbalance causing the abnormal endometrial growth. The correct hormonal therapy aims to induce a receptive endometrium for implantation.

**Why the Correct Answer is Right:** For infertile women with a proliferative endometrial biopsy, the preferred hormone is **Estradiol (E2)**. Estradiol is the main estrogen responsible for endometrial proliferation and development of the endometrial lining. It prepares the endometrium for implantation by promoting endometrial growth, thickening the endometrial lining, and stimulating the production of progesterone receptors.

**Why Each Wrong Option is Incorrect:**

A. **Progesterone (P4):** Progesterone is essential for the maintenance and secretory phase of the menstrual cycle, but in an infertile woman, we need to induce the proliferative phase first, which Estradiol does.

B. **Gonadotropin-releasing hormone (GnRH) agonists:** These drugs induce a rapid drop in estrogen and progesterone levels, which may be detrimental in an infertile woman as it would not induce the proliferative phase before suppressing hormones.

C. **Gonadotropins (FSH and LH):** These hormones are involved in follicle growth and ovulation, not endometrial proliferation. Additionally, exogenously administered gonadotropins can lead to hyperstimulation syndrome in some cases.

D. **Luteinizing hormone (LH):** As mentioned earlier, LH is involved in follicle development and ovulation rather than endometrial proliferation.

**Clinical Pearl:** In the treatment of infertility, it is essential to prioritize the induction of the proliferative phase with Estradiol before initiating progesterone or considering gonadotropins or GnRH agonists. This sequential hormonal therapy helps in preparing the endometrium for successful implantation and prevents complications like hyperstimulation syndrome.