**Core Concept**
Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders caused by mutations in genes involved in the synthesis of cortisol and aldosterone from cholesterol in the adrenal cortex. This leads to a deficiency in these steroid hormones and an accumulation of precursor hormones, resulting in an overproduction of androgens.

**Why the Correct Answer is Right**
The most common form of CAH is 21-hydroxylase deficiency, accounting for approximately 90-95% of cases. This deficiency occurs due to mutations in the CYP21A2 gene, which encodes the enzyme 21-hydroxylase. The enzyme is crucial for the conversion of 17-hydroxyprogesterone to 11-deoxycortisol in the adrenal cortex. Without sufficient 21-hydroxylase activity, the adrenal glands produce excessive amounts of androgens, leading to virilization of female infants and precocious puberty in both males and females.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided. Please provide the complete question with all options.
**Option B:** This option is not provided. Please provide the complete question with all options.
**Option C:** This option is not provided. Please provide the complete question with all options.
**Option D:** This option is not provided. Please provide the complete question with all options.

**Clinical Pearl / High-Yield Fact**
The classic presentation of CAH in females is ambiguous genitalia at birth, with an enlarged clitoris and a fused labia. This is due to the excessive production of androgens, which stimulate the growth of male genitalia in both males and females.

**Correct Answer:** D.