**Core Concept**
The patient's presentation of primary amenorrhea, well-developed breasts, and absence of pubic or axillary hair suggests a disorder of sex development (DSD) or a specific endocrine disorder affecting puberty and reproductive function. The absence of hirsutism points towards a condition that does not involve excessive androgen production.

**Why the Correct Answer is Right**
The patient's presentation is most consistent with Turner syndrome, a genetic condition characterized by the absence of one X chromosome (45,X). This results in ovarian dysgenesis, leading to estrogen deficiency and primary amenorrhea. The presence of well-developed breasts suggests estrogen exposure, likely due to peripheral conversion of androgens to estrogens. The absence of pubic or axillary hair is consistent with low androgen levels.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely referring to Congenital Adrenal Hyperplasia (CAH), which can present with primary amenorrhea and virilization (hirsutism), making it a less likely diagnosis in this case.
**Option B:** This option is likely referring to Androgen Insensitivity Syndrome (AIS), which typically presents with a male phenotype despite the presence of testes and a Y chromosome. This patient's presentation with well-developed breasts and absence of hirsutism makes AIS less likely.
**Option C:** This option is likely referring to Polycystic Ovary Syndrome (PCOS), which typically presents with oligomenorrhea or amenorrhea, but also often with signs of hyperandrogenism such as hirsutism, acne, and male pattern baldness. This patient's absence of hirsutism makes PCOS less likely.

**Clinical Pearl / High-Yield Fact**
In patients with primary amenorrhea and well-developed breasts, consider Turner syndrome as a diagnosis, especially in the absence of hirsutism or virilization. Turner syndrome is often associated with short stature, and patients may have a variety of physical characteristics such as a webbed neck, low-set ears, and a broad chest.

**Correct Answer: C.**