**Core Concept**
Calcium channel blockers (CCBs) are a class of medications that inhibit the influx of calcium ions into cardiac and smooth muscle cells, thereby reducing muscle contraction and vascular tone. Cerebral vasodilatation refers to the widening of blood vessels in the brain, which can lead to increased cerebral blood flow and potentially elevated intracranial pressure.

**Why the Correct Answer is Right**
The correct answer is a CCB that preferentially affects L-type calcium channels in vascular smooth muscle, leading to vasodilatation. Verapamil, a member of the dihydropyridine class of CCBs, has a unique property of causing cerebral vasodilatation due to its ability to cross the blood-brain barrier and affect L-type calcium channels in cerebral vessels. This effect is not seen with other CCBs like nifedipine or amlodipine, which are more selective for peripheral vascular smooth muscle.

**Why Each Wrong Option is Incorrect**
**Option A:** Nifedipine is a dihydropyridine CCB that primarily affects peripheral vascular smooth muscle and does not cross the blood-brain barrier, making it less likely to cause cerebral vasodilatation.

**Option B:** Amlodipine is another dihydropyridine CCB that is primarily used to treat hypertension and angina, and it does not have a significant effect on cerebral vessels.

**Option C:** Diltiazem is a non-dihydropyridine CCB that affects both cardiac and vascular smooth muscle, but it does not have a significant effect on cerebral vasodilatation.

**Clinical Pearl / High-Yield Fact**
Verapamil's unique property of causing cerebral vasodilatation is an important consideration in patients with conditions like hypertension, coronary artery disease, and heart failure, where calcium channel blockade may be beneficial.

**Correct Answer:** B. Amlodipine