**Core Concept**
Uterine fibroids, also known as leiomyomas, are benign tumors that arise from the smooth muscle layer of the uterine wall. They are a common cause of abnormal uterine bleeding and can be associated with pelvic pain, pressure symptoms, and infertility.

**Why the Correct Answer is Right**
All fibroids are derived from the same embryonic cells, which are the same cells that give rise to the smooth muscle of the uterus. This is why they are typically composed of smooth muscle and fibrous connective tissue. The growth and development of fibroids are influenced by estrogen and progesterone, which is why they often shrink after menopause. The genetic mutations that occur in fibroids can lead to uncontrolled cell growth and tumor formation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the origin or development of fibroids.
**Option B:** This option is incorrect because fibroids are not a type of epithelial tumor.
**Option C:** This option is incorrect because fibroids are not a type of vascular tumor.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that fibroids can be classified based on their location within the uterus, with submucosal fibroids being the most likely to cause symptoms due to their proximity to the uterine cavity.

**Correct Answer: B. Uterine fibroids are benign tumors that arise from the smooth muscle layer of the uterus.**