**Core Concept**
The development of the ovary in humans is a complex process that involves the formation of the genital ridge, a critical anatomical structure in the early stages of embryogenesis. The genital ridge is a thickening of the coelomic epithelium, which eventually gives rise to the gonads (ovaries or testes). This process is influenced by a cascade of genetic and hormonal signals that regulate the formation of the reproductive system.

**Why the Correct Answer is Right**
The correct answer, B. Genital ridge, is supported by the fact that the genital ridge is the primary site of ovary development. During embryogenesis, the genital ridge forms from the thickening of the coelomic epithelium, which is later invaginated to form the gonadal primordium. The gonadal primordium then undergoes a series of complex cellular transformations, including the formation of the cortex and medulla, which eventually give rise to the adult ovary. The presence of SRY protein and other genetic factors also plays a crucial role in the differentiation of the genital ridge into ovaries.

**Why Each Wrong Option is Incorrect**
**Option A:** Mullerian ducts are responsible for the development of the female reproductive tract, including the fallopian tubes, uterus, and upper vagina. However, they do not contribute to the formation of the ovaries themselves.
**Option C:** The genital tubercle is a critical structure in the development of the external genitalia, but it is not involved in the formation of the ovaries.
**Option D:** The mesonephric ducts, also known as Wolffian ducts, contribute to the development of the male reproductive system, but they are not involved in the formation of the ovaries.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that the formation of the ovaries is a complex process that involves the interplay of multiple genetic and hormonal factors. Abnormalities in this process can lead to disorders of sex development (DSD), highlighting the importance of a thorough understanding of embryogenesis in clinical practice.

✓ Correct Answer: B. Genital ridge.