**Core Concept**
Centchroman, also known as Ormeloxifene, is a non-steroidal selective estrogen receptor modulator (SERM) used as a contraceptive agent and for the treatment of dysmenorrhea and menorrhagia. Its unique mechanism involves selective binding to estrogen receptors, exerting agonistic effects on bone and lipid metabolism while exhibiting antagonistic effects on the endometrium.

**Why the Correct Answer is Right**
Centchroman's contraceptive efficacy is attributed to its ability to inhibit implantation by binding to estrogen receptors in the endometrium, thereby preventing endometrial growth and differentiation. This action is mediated through the selective modulation of estrogen receptors, particularly ERβ, which plays a crucial role in the regulation of endometrial function. The weekly dosing regimen of Centchroman allows for sustained plasma levels, ensuring consistent receptor binding and optimal contraceptive efficacy.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, so we cannot evaluate its correctness.
**Option B:** Incorrect, as the weekly dose of Centchroman is not specified in this option.
**Option C:** Incorrect, as Centchroman's dosing regimen does not involve this frequency or amount.

**Clinical Pearl / High-Yield Fact**
Centchroman's unique mechanism of action as a selective estrogen receptor modulator sets it apart from other hormonal contraceptives, making it an attractive option for patients seeking a non-hormonal or alternative form of contraception. Its efficacy in treating dysmenorrhea and menorrhagia also underscores its potential benefits in managing menstrual-related disorders.

**Correct Answer:** C. 30 mg