**Core Concept**
Feminizing ovarian tumors are a type of sex cord-stromal tumor that produce estrogen, leading to feminization in affected individuals. These tumors can cause a range of symptoms, including virilization, hirsutism, and breast tenderness in males, and menstrual irregularities and gynecomastia in females.

**Why the Correct Answer is Right**
The correct answer is **Granulosa cell tumor**. Granulosa cell tumors are a type of sex cord-stromal tumor that produce estrogen, which can lead to feminization. They are the most common type of sex cord-stromal tumor and can cause a range of symptoms, including menstrual irregularities and gynecomastia. The estrogen produced by granulosa cell tumors can also stimulate the growth of endometrial tissue, leading to endometrial hyperplasia and potentially even endometrial cancer.

**Why Each Wrong Option is Incorrect**
**Option A:** **Sertoli-Leydig cell tumor** is a type of sex cord-stromal tumor that produces androgens, leading to virilization in affected individuals. It is not a feminizing tumor.
**Option B:** **Dysgerminoma** is a type of germ cell tumor that does not produce estrogen or other sex hormones. It is not a feminizing tumor.
**Option C:** **Endodermal sinus tumor** is a type of germ cell tumor that produces alpha-fetoprotein, not estrogen. It is not a feminizing tumor.

**Clinical Pearl / High-Yield Fact**
Granulosa cell tumors are often associated with estrogen-producing symptoms, such as menstrual irregularities and gynecomastia. They can also cause endometrial hyperplasia and potentially even endometrial cancer due to the stimulation of endometrial tissue by estrogen.

**Correct Answer:** C. Granulosa cell tumor.