**Core Concept**
Hypertensive intracerebral hemorrhage (ICH) is a type of stroke caused by the rupture of small blood vessels in the brain due to chronic high blood pressure. This leads to bleeding into the surrounding brain tissue, resulting in damage to the brain and potentially life-threatening complications.

**Why the Correct Answer is Right**
The commonest site for hypertensive ICH is the basal ganglia, particularly the putamen. This is because the small blood vessels in this region are more susceptible to damage from chronic hypertension, leading to a higher risk of rupture and bleeding. The basal ganglia are a deep brain structure involved in movement control and cognition, and are richly supplied with small blood vessels that are prone to hypertensive damage.

**Why Each Wrong Option is Incorrect**
**Option A:** Cerebellum - While the cerebellum can be involved in hypertensive ICH, it is not the commonest site. The cerebellum is responsible for coordinating movement and balance, and is less frequently affected by hypertensive bleeding.
**Option B:** Pons - The pons is a part of the brainstem that connects the cerebrum to the spinal cord, and is not typically involved in hypertensive ICH. The brainstem is a critical structure that regulates many essential functions, and is often spared in hypertensive bleeding.
**Option C:** Cerebral cortex - The cerebral cortex is the outer layer of the brain responsible for processing sensory information and controlling movement. While it can be involved in hypertensive ICH, it is not the commonest site.

**Clinical Pearl / High-Yield Fact**
Remember the "BASILAR" acronym to help you remember the common sites of hypertensive ICH: Basal ganglia, Anterior limb of the internal capsule, Subthalamus, Inferior cerebellar peduncle, and Lateral pons.

**Correct Answer: C. Putamen.**