**Core Concept:** Benign Prostatic Hyperplasia (BPH) is a common condition in elderly males, characterized by the enlargement of the prostate gland. The prostate gland is composed of lobes: anterior, posterior, left, and right. When assessing the involvement of BPH, it is essential to understand which lobes are most commonly affected.

**Why the Correct Answer is Right:** In BPH, the most common lobe affected is the **posterior lobe**. This is due to its unique anatomical location and the high concentration of smooth muscle cells and α1-adrenergic receptors in this lobe. The posterior lobe has a high density of smooth muscle cells and α1-adrenergic receptors, which makes it more susceptible to hypertrophy.

**Why Each Wrong Option is Incorrect:**

A. **Anterior Lobe:** Though BPH can affect the anterior lobe, it is less common compared to the posterior lobe.

B. **Left Lobe:** While both left and right lobes can be involved, the posterior lobe being more common does not mean the left lobe is less involved.

C. **All Lobes Equally:** BPH is not evenly distributed across all lobes, but the posterior lobe stands out due to its specific anatomy and receptor distribution.

D. **None of the Above:** The correct answer is present, making this option incorrect.

**Clinical Pearl:** Understanding the distribution of BPH involvement helps guide clinical decision-making, such as selecting the appropriate biopsy site during prostate examination or assessing the need for surgical intervention.

**Correct Answer:** **Posterior Lobe**.