**Core Concept**
The genital tubercle is a critical embryological structure that gives rise to various parts of the external genitalia in both males and females. In females, the development of the genital tubercle is influenced by the absence of androgens, leading to the formation of a specific part of the external genitalia.

**Why the Correct Answer is Right**
In females, the absence of androgens prevents the differentiation of the genital tubercle into a penis and scrotum, as seen in males. Instead, the genital tubercle develops into the clitoris, which is a homologue of the penis in males. The clitoris is formed by the fusion of the genital tubercle with the urethral and labial swellings. The lack of androgen influence also leads to the formation of a vulva, which is composed of the labia majora, labia minora, and the vestibule of the vagina.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately reflect the development of the genital tubercle in females. The labia majora are formed from the labial swellings, not the genital tubercle.
**Option B:** This option is incorrect because it does not accurately reflect the development of the genital tubercle in females. The urethral opening is formed from the urogenital sinus, not the genital tubercle.
**Option C:** This option is incorrect because it does not accurately reflect the development of the genital tubercle in females. The vagina is formed from the paramesonephric ducts (Müllerian ducts), not the genital tubercle.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the development of the external genitalia is influenced by the presence or absence of androgens during embryogenesis. Understanding this concept is critical for diagnosing and managing disorders of sex development.

**Correct Answer:** D.