**Core Concept**
Clomiphene citrate is a medication used in the treatment of infertility in women, particularly those with polycystic ovary syndrome (PCOS). It acts by stimulating the release of gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH), which in turn stimulate ovulation. The medication contains two isomers: zuclomiphene and enclomiphene.

**Why the Correct Answer is Right**
Enclomiphene is the active antiestrogenic isomer of clomiphene citrate. It binds to estrogen receptors in the hypothalamus, which leads to an increase in the release of gonadotropin-releasing hormone (GnRH). This results in the increased release of FSH and LH, stimulating follicular growth and ovulation. The antiestrogenic effect of enclomiphene is essential for its mechanism of action.

**Why Each Wrong Option is Incorrect**
**Option B:** The actual increase in the chance of pregnancy with clomiphene citrate is around 10-20% compared to placebo, not threefold.
**Option C:** The risk of multiple pregnancy with clomiphene citrate is indeed higher, ranging from 8-12%, not 2-4%.
**Option D:** Clomiphene citrate is not typically used for male infertility with oligozoospermia. It is primarily used to stimulate ovulation in women.

**Clinical Pearl / High-Yield Fact**
It is essential to note that clomiphene citrate can cause a range of side effects, including hot flashes, breast tenderness, and mood changes. Patients should be counseled on these potential side effects and monitored closely during treatment.

**✓ Correct Answer: A. Enclomiphene has antiestrogenic affect**