## Core Concept
The question pertains to Congenital Adrenal Hyperplasia (CAH), a group of autosomal recessive disorders that affect the adrenal glands' ability to produce cortisol and/or aldosterone. The most common cause of CAH is 21-hydroxylase deficiency. Prenatal treatment aims to reduce fetal virilization in affected females.

## Why the Correct Answer is Right
The correct answer involves administering **Dexamethasone** to the mother. Dexamethasone is a synthetic glucocorticoid that can cross the placenta and suppress fetal adrenal androgen production, thereby reducing virilization in female fetuses with CAH. This treatment is considered when there is a high risk of CAH in the fetus, typically in families with a known history of the disorder. The goal is to prevent or minimize virilization of female genitalia, which can occur due to excessive fetal adrenal androgen production.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is blank and does not provide a viable treatment choice.
- **Option B:** This option is also blank and does not offer a valid treatment alternative.
- **Option C:** Similarly, this option is blank and lacks a specific treatment.
- **Option D:** This option is blank as well.

## Clinical Pearl / High-Yield Fact
A crucial point to remember is that prenatal treatment with dexamethasone is only offered when the risk of CAH is high, and after thorough genetic testing and counseling. The treatment's effectiveness and risks, including potential effects on fetal growth and maternal health, must be carefully weighed.

## Correct Answer Line
**Correct Answer: C. Dexamethasone.**