**Core Concept**
Subepithelial deposits refer to the accumulation of immune complexes or other substances beneath the epithelial layer in various tissues, often associated with autoimmune diseases. This phenomenon is characterized by the presence of deposits in the subepithelial space, which can lead to inflammation and tissue damage.

**Why the Correct Answer is Right**
Subepithelial deposits are typically seen in conditions like lupus nephritis, where immune complexes accumulate in the glomeruli beneath the glomerular basement membrane. This leads to complement activation, leukocyte infiltration, and subsequent tissue damage. The presence of subepithelial deposits is often associated with the deposition of IgG and C3.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because subepithelial deposits are not typically seen in conditions like membranous nephropathy, where the deposits are usually found in the subepithelial space but are composed of immune complexes and are often associated with the deposition of IgG and C3.

**Option B:** This option is incorrect because subepithelial deposits are not typically seen in conditions like diabetic nephropathy, where the primary pathology involves thickening of the glomerular basement membrane and mesangial expansion.

**Option C:** This option is incorrect because subepithelial deposits are not typically seen in conditions like minimal change disease, where the primary pathology involves loss of foot processes and podocyte effacement.

**Clinical Pearl / High-Yield Fact**
When evaluating patients with suspected autoimmune diseases, it's essential to consider the presence of subepithelial deposits, which can be a hallmark of conditions like lupus nephritis. This knowledge can guide further diagnostic testing and inform treatment decisions.

**Correct Answer: D. Lupus Nephritis**