**Core Concept**
Benign hypertension, also known as essential hypertension, is a condition characterized by elevated blood pressure without an identifiable secondary cause. Histologically, its effects on the kidney are a crucial aspect of understanding this condition.

**Why the Correct Answer is Right**
The commonest histological finding in benign hypertension is the thickening of the media in small arteries and arterioles, particularly in the glomerular arterioles. This thickening is due to the proliferation and hypertrophy of smooth muscle cells, leading to an increase in the thickness of the arterial wall. This change is often referred to as "onion-skinning" or "hyaline arteriolosclerosis." The increased resistance to blood flow in these vessels contributes to the elevated blood pressure seen in benign hypertension.

**Why Each Wrong Option is Incorrect**
**Option A:** Fibrinoid necrosis is more commonly associated with malignant hypertension, which is characterized by severe and acute blood pressure elevation. It involves the deposition of fibrin and other proteins in the arterial wall, leading to necrosis and damage to the vessel.

**Option B:** Arterial calcification is a feature of chronic kidney disease or atherosclerosis, rather than benign hypertension. It involves the deposition of calcium salts in the arterial wall, leading to hardening and stiffening of the vessels.

**Option C:** Glomerulosclerosis is a feature of diabetic nephropathy, rather than benign hypertension. It involves the scarring and thickening of the glomerular basement membrane, leading to impaired kidney function.

**Clinical Pearl / High-Yield Fact**
The "onion-skinning" appearance of the arterial walls in benign hypertension is a classic histological finding that should be remembered by students.

**Correct Answer: C. Arterial thickening and hyaline arteriolosclerosis.**