**Core Concept**
Leprosy, also known as Hansen's disease, is a chronic infectious disease caused by **Mycobacterium leprae** that primarily affects the skin, nerves, and mucous membranes. Renal involvement in leprosy can occur due to various mechanisms, including immune complex deposition and direct bacterial invasion.

**Why the Correct Answer is Right**
The most common renal manifestation of leprosy is **glomerulonephritis**, particularly **immune complex-mediated glomerulonephritis**, resulting from the deposition of antibodies against **Mycobacterium leprae** in the glomeruli. This leads to inflammation and damage to the renal tissue, impairing its function.

**Why Each Wrong Option is Incorrect**
**Option A:** Not a common renal manifestation of leprosy.
**Option B:** Not directly related to leprosy.
**Option C:** Not the most common renal manifestation.

**Clinical Pearl / High-Yield Fact**
Leprosy can cause a wide range of renal abnormalities, but **glomerulonephritis** is the most significant and common one, often presenting with **hematuria** and **proteinuria**.

**Correct Answer:** D. Glomerulonephritis