**Core Concept**
The prostate gland is a vital part of the male reproductive system, playing a crucial role in the production of semen and the regulation of urine flow. It is a complex organ with both glandular and muscular components, making it susceptible to various pathologies.

**Why the Correct Answer is Right**
The correct answer is **C. Smooth muscle**. The prostate gland contains a significant amount of smooth muscle, which is essential for the regulation of urine flow and the contraction of the gland during ejaculation. The smooth muscle cells in the prostate are innervated by the autonomic nervous system, allowing for involuntary control over the gland's function. This unique combination of glandular and muscular tissue makes the prostate a fascinating and complex organ.

**Why Each Wrong Option is Incorrect**
* **Option A:** While the prostate gland does contain some fibromuscular tissue, it is not the primary component.
* **Option B:** Prostatic adenocarcinoma is a type of cancer that originates from the glandular tissue of the prostate, but it is not a feature of the gland's normal anatomy.
* **Option D:** The urothelium is a type of epithelial tissue that lines the urinary bladder and ureters, but it is not a component of the prostate gland.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the prostate gland's muscular component can lead to benign prostatic hyperplasia (BPH), a common condition characterized by the enlargement of the gland and subsequent urinary symptoms.

**Correct Answer: C. Smooth muscle**