**Core Concept**
Proliferative glomerular deposits refer to the accumulation of immune complexes or other substances within the glomeruli of the kidney, leading to inflammation and damage. This condition is associated with various kidney diseases, including lupus nephritis and post-streptococcal glomerulonephritis.

**Why the Correct Answer is Right**
The correct answer involves the deposition of immune complexes, which triggers an inflammatory response and leads to glomerular proliferation. This process is mediated by the activation of complement system, specifically the classical pathway, which results in the formation of C3 convertase and the subsequent activation of C5b-9 (membrane attack complex). The glomerular basement membrane is damaged, leading to the accumulation of immune complexes and the activation of various immune cells, including macrophages and T cells.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because proliferative glomerular deposits are not typically associated with conditions involving the deposition of amyloid fibrils.
**Option B:** This is incorrect because while IgA nephropathy is a cause of kidney disease, it is not specifically associated with proliferative glomerular deposits.
**Option C:** This is incorrect because membranous nephropathy is characterized by the deposition of immune complexes on the subepithelial side of the glomerular basement membrane, rather than within the glomeruli themselves.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the presence of proliferative glomerular deposits is often associated with a poor prognosis and a higher risk of kidney failure.

**Correct Answer:** D.