**Core Concept**
Prophylactic administration of a specific medication is a preventive measure aimed at reducing the risk of developing breast cancer in high-risk individuals. This approach is based on the understanding that certain genetic mutations, such as BRCA1 and BRCA2, significantly increase the likelihood of breast cancer development.

**Why the Correct Answer is Right**
The correct answer involves the administration of tamoxifen, a selective estrogen receptor modulator (SERM), which has been shown to reduce the incidence of breast cancer in high-risk women. Tamoxifen works by binding to estrogen receptors on breast tissue, thereby inhibiting the growth-promoting effects of estrogen. This mechanism is particularly effective in individuals with a high risk of breast cancer, such as those with a BRCA1 or BRCA2 mutation.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not specify a medication that has been proven to reduce breast cancer risk.
* **Option B:** This option is incorrect as it does not accurately represent a medication that is commonly used for breast cancer prevention.
* **Option C:** This option is incorrect as it suggests a medication that is not typically used for breast cancer prevention.

**Clinical Pearl / High-Yield Fact**
It is essential to identify high-risk individuals for breast cancer, such as those with a strong family history or known genetic mutations. Early intervention with prophylactic medications like tamoxifen can significantly reduce the risk of breast cancer development in these individuals.

**Correct Answer:** C. Tamoxifen.