**Core Concept**
Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder affecting women of reproductive age, characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. The pathophysiology of PCOS involves insulin resistance, which is a major risk factor for developing type 2 diabetes mellitus.

**Why the Correct Answer is Right**
Insulin resistance is a common feature in PCOS patients, resulting from impaired insulin signaling and decreased glucose uptake in peripheral tissues. This leads to compensatory hyperinsulinemia, which in turn contributes to androgen excess and ovulatory dysfunction. Studies have shown that a significant proportion of PCOS patients have impaired glucose tolerance or type 2 diabetes mellitus, highlighting the importance of screening for diabetes in this population.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not accurately reflect the prevalence of diabetes in PCOS patients. The actual prevalence is higher than this option suggests.
* **Option B:** This option is incorrect as it is too low and does not account for the significant risk of diabetes in PCOS patients. Insulin resistance is a key feature of PCOS, increasing the risk of developing type 2 diabetes.
* **Option D:** This option is incorrect as it is too high and may not accurately reflect the actual prevalence of diabetes in PCOS patients.

**Clinical Pearl / High-Yield Fact**
It's essential to screen PCOS patients for insulin resistance and diabetes, particularly those with a family history of type 2 diabetes or other risk factors. Regular monitoring of glucose levels and lipid profiles can help identify patients at risk and allow for early intervention.

**Correct Answer:** C. 10-30%